Boris Johnson's coronavirus testing fiasco was thrown into sharp relief today with pictures showing NHS workers queuing for one screening site - while another was deserted.
The government is desperately trying to ramp up the number of checks carried out, amid warnings that 85 per cent of self-isolating NHS staff might be off unnecessarily due to a lack of screening.
But there were chaotic scenes at new drive-through 'swab stations', with one site in Chessington barely seeing any traffic, but another just 13 miles away in Wembley rammed.
Doctors, engineers and administrators complained they had been turned away from both locations because they had not booked formal appointments.
The turmoil emerged with the PM facing mounting fury over the failure to get anywhere near the testing levels being carried out in countries like Germany - which is carrying out more than 70,000 a day, while the UK is still well below 10,000.
Putting a mass regime in place will be vital before easing the lockdown strangling the economy and threatening millions of jobs.
Shortages of chemicals and swabs have surfaced as critical problems, with the government scrambling to get hold of 'reagents' needed to process samples.
The head of NHS Providers said the UK could be carrying out 100,000 tests per day if it were not for those issues.
But the lack of availability for those on the frontline of the battle in hospitals is causing the most immediate concern.
The first smattering of testing for NHS staff who were isolating over the weekend suggested just 15 per cent have the virus - meaning tens of thousands could potentially have been working. It is understood just 2,000 have been screened so far.
In desperate a bid to increase testing levels for staff, hospitals have been ordered to use any spare lab space to test self-isolating NHS staff, rather than reserving 85 per cent of checks for patients.
Health Secretary Matt Hancock intervened after thousands of tests were left unused yesterday.
Housing Secretary Robert Jenrick today admitted that the level of checks had only been rising slowly, but suggested it would 'accelerate'. However, he confirmed it will be weeks before the UK hits 25,000 tests a day, by which time the outbreak might be peaking.
In another helter-skelter as the UK was rocked by the announcement of 563 more coronavirus deaths, taking the total toll to 2,352:
There was little activity at the Chessington coronavirus testing site today which was set up as a drive-thru for NHS workers who need to get tested
Another coronavirus swab testing site for NHS staff at Ikea in Wembley, west London was much busier today
Staff were hard at work testing NHS staff at the facility in west London today, despite the deserted scenes at Chessington
What chemicals are needed for coronavirus tests?
Most tests for whether people currently have coronavirus are based on a PCR (polymerase chain reaction) process.
That aims to pick up on active viruses currently in the bloodstream.
A PCR test works by a sample of someone's genetic material - their RNA - being taken to lab and worked up in a full map of their DNA at the time of the test.
But this requires the generation of a chemical reaction to amplify the signal, and 'reagents' are used to make this happen.
Reagents known as 'primers' and 'DNA polymerase' are especially important.
They are produced by specialist biotechnology companies - many of which are based in Germany.
Despite ministers insisting at the weekend that 10,000 tests were being carried out a day, But only 8,630 were carried out on Monday. The government says total testing capacity is 12,750.
A huge NHS coronavirus swabbing site at Chessington is barely being used again today despite the urgent need for more patients and medics to be examined.
But footage taken by 5 News Chief Correspondent Tessa Chapman showed one at Ikea in Wembley was packed, suggesting planning has been at fault.
An NHS emergency engineer said he had been refused a test at Chessington due to not having an appointment.
The engineer, from Brighton, East Sussex, told MailOnline: 'It's my job to fix vital equipment in the hospital. Yesterday I had to fix a sink in a ward with Covid-19 patients.
'So I'm off work today, but I want to get back as soon as possible.
'But they won't give me a test because I don't have an appointment. It's mad. I've driven up from Brighton just for this test, it's completely empty and they won't let me take the test! Why not?'
Separately, an administrator from Surrey told MailOnline: 'My husband is in hospital with the Coronavirus. He's not been very well.
'But there are people depending on me at work.
'I've had to isolate because my husband has got it. So I can't go back to work until I know I'm clear.'
At Wembley, a doctor flashed his NHS laminated ID pass at the security guard but was told to turn around and leave.
He told MailOnline he had a letter from his head of department requesting a test but without an email from Public Health England with a specific appointment time he would not be tested.
'I wasn't on shift so decided to come down and try to get a test but without an email appointment they will not let you in,' he said.
'It does seem a bit absurd that NHS workers are unable to turn up when they have a spare moment to get tested.'
Many of those who joined the queue into the car park at the store were members of the public hoping to get a test.
Some were unaware that it was only for NHS frontline workers but others were hoping to squeeze in during a quiet period in the afternoon.
Two builders arrived in a transit van and looked surprised when they were told to do a U-turn and exit the line into IKEA.
Everyone arriving was stopped by a security guard in a high viz jacket carrying a sign which asked them to keep their windows shut.
Car occupants were instructed to show their NHS ID and a letter of appointment before proceeding to another checkpoint where their names checked against a list.
Queues built up at the Wembley test centre but by mid-afternoon the number of people arriving had declined. More than 400 have been screened there since Sunday.
Mum Susan Parsley, 38, drove from nearby Neasden in the hope of getting a test.
'I heard about the test centre on the news and decided to see if I could get a test. I know it is meant for NHS workers but thought if it was very quiet I might be able to get tested.'
Two teenage girls also arrived only to be asked to leave.
'We didn't know it was only for NHS people. We did not want to jump any queue but as we are bored came down here,' said one of the teens.
A security guard told MailOnline many of those queuing had no idea it was for NHS staff only.
Even shoppers joined the queue with one woman irate that she couldn't pop into the store to buy a picture frame.
'Some people have no clue what's going on and how serious this is,' said one of the guards at the entrance.
Some 30 NHS staff were tested for Covid-19 at the Chessington site this afternoon.
All had had an appointment booked and confirmed by their NHS Trust.
These staff members are required to show an email from Public Health England confirming their test appointment and their NHS registration to staff at the entrance of the site before they are admitted for the swab.
How the UK's testing shambles developed
January 31: First confirmed cases in the UK are two Chinese nationals staying in York.
February 21: Government experts conclude at a meeting that the disease is still only a 'moderate' threat to the UK.
March 12: The UK shelves efforts to test and 'contact trace' everyone with symptoms on March 12, as the government's response moves from 'containment' into a 'delay' phase.
Instead people who think they have the illness are urged to self-isolate unless their conditions became so severe they need medical help.
March 16: Boris Johnson urges Britons to follow 'social distancing' guidelines as well as isolating when they have symptoms, in a change of policy after modelling found the death toll could be much higher than previously estimated.
March 18: Amid growing criticism, the PM declares that there will be a big expansion of tests from under 5,000 a day to 25,000.
March 21: Downing Street sends an email to research institutions begging for machines needed to process testing samples. No10 denies this was the first time it had raised the idea.
March 28: Cabinet ministers Matt Hancock and Michael Gove hail news that the UK is now carrying out 10,000 tests a day.
April 1: The UK has still not carried out 10,000 tests in a day, despite apparently having the capacity to do so.
Ministers admit the target of 25,000 tests a day might not be reached for weeks.
Chris Hopson, Chief Executive of NHS providers, estimated that 15 per cent of NHS staff were off work, and initial testing over the weekend had found that just 15 per cent of those self-isolating were infected with coronavirus.
'It's a very, very small sample size because we only really started doing staff testing properly Saturday-Sunday, but I'm told that the very early results from that very small sample did indicate that only 15 per cent of people taking the test were positive which effectively means that the other 85 per cent are potentially available to come back to work.'
Mr Hopson said he believes an average of 15 per cent of all NHS staff are currently off work and urged the Government to give an estimate of how quickly testing capacity can be ramped up.
'Our understanding is that as of the middle of... the late end of last week it was about 15 per cent of NHS staff, which given the sickness rate, absence rate that you would normally expect to see in the NHS of around I think 3-4 per cent, you can see how big that gap is.'
Responding to reports that up to 50 per cent of NHS staff are off work, he added: 'We certainly know that some of the outlying trusts were very high... much higher than 15 per cent. The 15 per cent figure is effectively the average across all NHS staff.
'What you would expect is that you would see trusts with higher level of absence... I don't want to speculate about whether you would expect to see higher levels of absence among frontline clinicians, but we know that in some trusts this is a real issue.'
Mr Hopson tweeted earlier: 'We understand that if existing NHS pathology labs had unlimited swabs and reagent there is enough test machine capacity to process c100,000 tests a day but reagent and swab shortage is currently limiting this to c13k a day. Shows impact of shortages on current test capacity.'
It has also emerged that a British firm producing millions of pounds worth of coronavirus tests is selling most of them abroad as the UK doesn't have enough laboratories to use them. Novacyt has made £17.8million selling its testing equipment to more than 80 countries via its Southampton-based subsidiary Primerdesign. But only £1million worth has been sold to the UK.
Mr Johnson is taking control of ensuring chemicals vital to test kits arrive in the UK amid the criticism. Mr Gove said at yesterday's Downing Street press conference: 'The prime minister and the health secretary are working with companies worldwide to ensure that we get the material we need to increase tests of all kinds.'
The claims of a shortage seemed to take the industry by surprise. The Chemical Industries Association said: 'While there is of course an escalating demand, there are reagents being manufactured and delivered to the NHS.
'Every business here in the UK and globally is looking at what they can do to help meet the demand as a matter of urgency.'
However, diagnostics industry group BIVDA confirmed that there are problems. Chief executive Doris-Ann Williams, said: 'Provision of the different tests for this new disease is challenging.
'The IVD (in vitro diagnostics) industry has been working to support the NHS to implement testing here in the UK, as it has been doing for healthcare systems around the world.
'This continues with manufacturers doing all they can to ensure continuous supply of the necessary reagents to enable antigen testing during this unprecedented crisis. However there is global demand and manufacturing capacity is being increased at pace along with the logistics to distribute it but none of this can be achieved overnight. But we can assure you that everything that can be done is being done.'
Trying to explain the discrepancy this morning, Mr Jenrick told BBC Breakfast: 'The chemicals industry have rightly said that in the UK we produce a number of the ingredients to produce the tests that we need.
'But to produce a reliable test you need to have a range of ingredients and not all of them, as I understand it, have always been available in the UK in the quantities that we need.
'But we are working with British manufacturers, as much as we possibly can and they have been extremely helpful and supportive in trying to ramp up production.'
Asked if the lack of chemicals was the reason for the delay, Mr Jenrick said: 'That is one of the reasons - that we have some of the ingredients, but not all of them. But the good news is that production is now increasing.'
He said other reasons for the delay in ramping up testing are 'the availability of the right infrastructure' and 'a very high degree of demand' for tests making importing from overseas difficult.
Tory MP Tobias Ellwood pointed out that Germany had firms like Roche based in the country, which is a leader in biotech. 'They are able to these things on site. We have a supply chain to deal with… there is a global competition for these products,' he told BBC Newsnight.
Meanwhile, there are complaints that the 'centralised' approach taken by Public Health England (PHE) meant that labs have been left 'sitting on their hands'.
Staff queue to be allowed into the newly-installed NHS Nightingale hospital at the ExCel centre in London today
It is still not clear when a new coronavirus 'super lab' in Milton Keynes will be up and running. In contrast, Germany has authorised any institution with the right capability to get on with checks.
Oxford University has 119 machines that can be used to identify tell-tale genetic signs of the virus, but Government officials have only so far accepted one.
Professor Matthew Freeman of Oxford University's Dunn School of Pathology, said: 'We have another 118 machines that can broadly do the same job, but they don't appear to be part of PHE's plans. They could be adapted easily.'
The Francis Crick Institute has supplied five machines to the NHS, but has dozens more that aren't being utilised in the fight against the pandemic.
Meanwhile, there are accusations that the government never planned for a situation where they would need to carry out mass testing.
'The UK was complacent and didn't think it could happen here,' said Tim Colbourn, associate professor of global health epidemiology at University College London. 'We didn't see the signs quickly.'
The Mail revealed today that a British firm is selling kits to 80 countries, including India.
Novacyt said a shortage of NHS testing facilities had prevented further UK sales.
Separately, a former World Health Organisation chief said yesterday the Government's health protection agency had been 'slow' over testing and that 44 labs were underused.
Science Committee chair Greg Clark, a former Cabinet minister, told MailOnline the reasons for the difficulty ramping up testing was still 'unexplained'.
'There are NHS workers now who are having to be self-isoated and not working because they have symptoms, but don't know whether they are infected or not
'If you stretch the NHS that is a big problem.
'It would be much better in information terms to know more accurately how many people in the population have it at the moment.
'We simply don't know. We know sadly who has died of it, but not who has it.
Mr Clark said there had been a clear shift from focusing on testing at the start of the crisis, to merely slowing the outbreak the 'delay' phase.
'I think it is an operational thing, that they didn't mobilise enough capacity in testing to be able to supply the needs of the country,' he said.
UK experts classed coronavirus a 'moderate' risk just five weeks ago
The deadly coronavirus was deemed a 'moderate risk' to Britain by top scientists five weeks ago, it has been revealed.
A Public Health England committee held a teleconference on February 21 to discuss the threat level of COVID-19 in the UK.
Minutes from that meeting show scientists and Whitehall observers raised 'no objections' to the risk level remaining moderate despite rapidly growing global figures.
However, one scientist, John Edmunds later made clear he disagreed and had been prevented from intervening on the call due to technical problems.
At the time, representatives from the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) were provided with recent data showing 75,465 cases of the virus confirmed in China alongside 2,236 fatalities.
But advisers from Nervtag concluded: 'Current PHE risk assessment of the disease is moderate.
'The PHE risk assessment to the UK population is also moderate. This is a composite of what is known about transmission and the impact on public health globally and in the UK.'
'Other countries such as Japan and South Korea have had a decentralised model of testing,
'Any lab that can test has been requisitioned for testing. What the PHE approach has been is to use their own labs. They started off at a single lab... then they moved to 122 labs and then more.
'My question on that is why do it in stages, why wasn't every lab even in the public sector used initially? And why unlike in Germany and SOuth Korea why have we not made extensive use of labs in universities for example and the private sector.'
In a chink of optimism for the government, Mr Clark said while the antigen testing for who currently has the disease was 'important' the antibody test was what would be 'crucial for the relief of the lockdown'.
'That would be the big gamechanger. It is very unfortunate that we haven't had the degree of antigen testing that other countries have had but if we deploy this at the scale of millions they are talking about that would allow us to catch up and be ahead of other countries.'
Shadow health secretary Jon Ashworth said: 'Germany are testing half a million people a week, yet we still haven't hit the 10,000 a day the Prime Minister promised.
'NHS staff are rightly asking if we've left it too late to buy the kits and chemicals we need, or whether our lab capacity is too overstretched after years of tight budgets.
'NHS staff and carers on the front line who need these tests urgently deserve an immediate explanation from the Government as to what's going on.'
A drive-thru test centre was established at Chessington World of Adventures and was seen up and has been operational since Friday.
In interviews today, housing Secretary Robert Jenrick insisted 'not all' the ingredients needed to produce reagents for tests were available
Paramedics and ambulances await their first patients at the huge temporary NHS Nightingale at London's ExCel centre today
'80 per cent of patients on ventilators will die'
Volunteers working at the NHS Nightingale coronavirus hospital have been told to prepare for the fact that up to 80 per cent of patients who are on ventilators will die, MailOnline can reveal.
Selfless heroes flocking to staff the emergency 4,000-bed unit in east London have been told to 'be prepared to see death', with a mortality rate of 50 to 80 per cent among those on ventilators.
There also appears to be a shortage of doctors already before it opens today, because of a lack of testing for medics, leaving senior nurse practitioners in charge on some wards.
Soldiers have played a key role in getting the unit open for business in just a week, with some comparing it to the First World War Battle of the Somme in being the biggest test of their careers.
But on Tuesday the site - which sits in one of the theme park's car parks - was quiet as Britain's daily fatalities figure surged more than twice as high as it was yesterday, when only 180 new fatalities were announced.
Office for National Statistics data showed today that 210 people had died in the UK by March 20, when the Government had only recorded 170 in the same time frame - a difference of almost a quarter. If that ratio remains true the true number of fatalities could be 2,230 or more.
One of the new victims was just 19 years old, from London, and didn't have any other health conditions, making them the UK's youngest otherwise-healthy patient to have died.
More than 3,000 infection cases were also recorded today, taking the UK's official outbreak size past 25,000 – but the true number remains a mystery because of the controversial policy to only test patients in hospital and not those with mild symptoms.
Some scientists have suggested up to half of the population may have already been infected but Government advisers suggest the figure is closer to the 2million mark.
On Thursday the government announced that it would be rolling out tests in an attempt to boost numbers on the front line.
Hospitals have been recording staff absence rates of up to 50 per cent as staff or members of their households develop symptoms which means they are forced to self-isolate as they do not know if they are safe to work.
Michael Gove, who was standing in for the prime minister at the daily briefing, said: 'Increasing our testing capacity is absolutely crucial in our response to and our fight against coronavirus.
'This is a particular priority for those who work in the health and social care sector and are working so hard to keep us all safe.'
10,000 NHS staff tell PM: We need proper protection
More than 10,000 frontline NHS staff have written to the Prime Minister to demand proper protective equipment amid growing anger that a lack of supplies is putting lives at risk.
Jenny Harries, the deputy chief medical officer, last night admitted there had been 'distribution issues' but insisted the UK had enough personal protective equipment (PPE) to cope with the pandemic.
Millions of masks, gloves, aprons and other items were delivered to hospitals on Monday, the Government said, with the Army helping to get them out nationwide.
Import taxes on such clothing, ventilators and virus testing kits have also been waived to ease supply, the Chancellor said.
But, despite this, unions representing healthcare workers say their members are complaining in droves about shortages of safety equipment. The GMB said some social care staff were being expected to make visits with just a plastic apron and a pair of gloves – 'the same protection that they use to make a sandwich.'
The letter to Boris Johnson has been co-ordinated by EveryDoctor, a membership organisation of UK doctors which campaigns on safety in the NHS.
It says NHS guidelines on what medics should wear to treat Covid-19 patients are not stringent enough and should be brought into line with World Health Organisation recommendations. The statement has been signed by more than 20,000 medics, including 10,000 who work in the NHS, in less than two days.
The Prime Minister's spokesman said: 'The full weight of the Government is behind the PPE effort with PPE being sent out 24 hours a day and the Army.'
The tests for NHS employees started with those who are critical care medics or intensive care staff but also includes those working in emergency departments, ambulance services and GPs.
Sir Simon Stevens, chief executive of the NHS, said that as testing volumes increased the service would be expanded to cover a range of essential public workers such as social care services.
A Department of Health and Social Care spokesperson said: 'The Chessington site has already tested hundreds of NHS key workers since being established in recent days and will play a vital role as national COVID-19 testing infrastructure is scaled up.
'Testing is a crucial part of the UK's response to the coronavirus pandemic and we have committed to boosting NHS testing to at least 25,000 a day for patients most in need, as well as testing thousands of healthcare workers a day in the near future.'
More deaths have been recorded in the UK, with 1,808 known fatalities when the individual tallies from Wales, Scotland and Northern Ireland are counted – but the official toll is lower because it cuts off at 5pm the day before, meaning the other fatalities recorded by the devolved nations will be added in to tomorrow's count.
Andy Burnham, a former health secretary and now Labour mayor of Greater Manchester, said ministers had implied they would have hit 25,000 tests a day by now.
He added: 'Widespread testing is a crucial weapon in the fight against this virus, both in terms of stopping its spread in the community, reassuring the public and getting frontline staff back to work.
'We need a national effort to help the Government hit its testing targets and that needs to start now.'
Liberal Democrat MP Layla Moran said: 'The Government needs to move faster on this; mass testing will help reduce the spread of the virus, better protect the key workers who are putting their lives on the line, and help the economy by allowing those who have had the virus to come out of isolation.'
Testing is particularly important for NHS staff as many are self-isolating for up to 14 days when either themselves or family members are showing virus symptoms.
Britain didn't properly prepare for coronavirus testing because it planned to rely on discredited 'herd immunity' strategy, claims leading scientist
The UK gave up on containing the coronavirus outbreak 'too soon' because scientists assumed most people would become infected anyway, a leading expert has claimed.
Devi Sridhar, professor of global public health at the Edinburgh University, said the assumption led officials to abandon measures that could help slow the pandemic.
Those measures include mass testing and stringent contact tracing - two actions which have helped South Korea keep COVID-19 fatalities below 200.
Early on in the UK's outbreak, the Government suggested one way of beating the virus was by allowing 80 per cent of Britons to get infected to build 'herd immunity'.
Professor Sridhar tweeted today that this kind of thinking 'resulted in the UK giving up on containment too early.'
'Planning and preparing for unprecedented testing and using big data/apps for tracing were taken off the table. In my view, we went down the wrong path,' she said.
It comes as a record-breaking 381 coronavirus deaths and 3,009 cases were declared in the UK today, which is now officially Britain's darkest day so far in the ever-worsening crisis.
Devi Sridhar, professor of global public health at the Edinburgh University, said the UK gave up 'too soon' on containing the coronavirus outbreak because scientists assumed most people would become infected anyway
Statistics released this morning revealed basic details about the first 108 people in Britain to have COVID-19 mentioned on their death certificate. Elderly people and men were the worst affected, the data showed
By March 20, the coronavirus had become a contributing factor or direct cause in one in every 100 deaths in the UK, according to the latest date from the Office for National Statistics
Britain has been slow to test - less than 5,000 daily swabs were being carried out until March, compared to South Korea's 15,000.
The UK also gave up on tracing infected patients' close contacts as cases began to surge and had to impose a nationwide quarantine to stop the virus' spread.
Whereas South Korea tracked down associates of infected patients and isolated them immediately, meaning it as not needed to enforce such draconian measures.
In a separate series of tweets she added that the UK's current lockdown was like 'pressing pause' on the virus' spread and 'playing catch up'.
'South Korea never had lockdown, only 152 deaths, and didn't expose health staff to unnecessary risk & pressure,' she said.
'Each day in lockdown: kids fall into poverty, domestic abuse increases, social fabric comes apart, major economic hit. Lockdowns are expensive. We need to use the time.
'We will be stuck in lockdown until we get test, trace, isolation plan. We are basically pressing pause on the spread of virus while we race to catch up.
'If we're not using the time now, then we're just wasting days/months in lockdown not aggressively figuring out where virus is.'
Michael Gove today said the UK must go 'further, faster' in ramping up its coronavirus testing efforts
CHEMICAL REAGENTS: NECESSARY FOR TESTING BUT IN HIGH GLOBAL DEMAND
A global shortage of the chemicals needed to produce coronavirus tests has emerged as another setback in the UK's plans to test more people.
Industry bosses say chemical reagents that are used in the test are in short supply around the world as countries have scrambled to test their citizens for COVID-19.
Lab tests for the coronavirus work by regrowing a patient's DNA in a lab and examining it to find traces of genetic material left behind by the SARS-CoV-2 virus.
For this to work, technicians need a chemical called a reagent to trigger the chemical reaction which starts the process.
There are various types of reagents which can be used in a COVID-19 test, supplied by different companies around the world, but they are in high demand everywhere. They are not unique to coronavirus and are the same reagents used in tests for illnesses such as flu.
The US has 10 different types of reagent listed in the priority list by the Centers of Disease Control and Prevention (CDC). It is not clear whether the UK is using reagents manufactured on home soil or importing them.
Some NHS labs have now resorted to make their own in 'home brew' situations so they can test patients, The Times reported.
Officials are now scrambling to see if there are alternatives to their first choice, according to the newspaper, and are also trying to shore up supplies of swabs, which are vital for tests.
CEO of pharmaceutical company Roche, Severin Schwan, said 'demand is outstripping supply' for the reagents. 'Widespread testing is simply not possible,' he added.
While the Professional Association of Laboratory Medics in Germany said: 'The materials required for testing - sample kits, materials for extracting samples, and reagents - are becoming scarce'.
The Australian Medical Association sounded the alarm there two weeks ago, when it said some parts of the government had failed to stockpile the right reagents, The Guardian reported.
It said global demand was 'exceeding supply' and that 'there are particular concerns around supplies of swabs and DNA extraction kits'.
Michael Gove today admitted the government's coronavirus testing operation must go 'further, faster' after Downing Street suggested a target of 25,000 daily checks may not be met until the end of next month.
The Minister for the Cabinet Office said the lack of availability of crucial chemicals which are needed in the testing process was a 'critical constraint' on the UK's efforts.
He said Boris Johnson and the Health Secretary Matt Hancock were now working together to try to source the globally in-demand material that Britain needs.
Speaking at the daily Downing Street press conference, Mr Gove said: 'While the rate of testing is increasing we must go further, faster. A critical constraint on the ability to rapidly increase testing capacity is the availability of the chemical reagents which are necessary in the testing.
'The Prime Minister and the Health Secretary are working with companies worldwide to ensure that we get the material we need to increase tests of all kinds.'
Critics today labelled the UK's efforts a 'catastrophe' and 'dismal' when compared to what is being done in Germany where 500,000 tests are being carried out every week.
Downing Street had earlier hinted at Mr Johnsons's apparent frustration at the slow progress on ramping up Britain's capacity, with a spokesman saying he wants 'as much progress to be made on this as possible'.
The UK is currently managing just under 10,000 tests a day with the government having previously said it wants to get to 25,000 by the middle of April.
But today Number 10 said the timetable was 'mid to late April' - seemingly an admission that efforts have stalled.
Politicians from different parties are now lining up to criticise the government's approach while business chiefs are doing the same.
Jeremy Hunt, the Tory former health secretary, said mass testing in the community must be carried out by the government while Brexit Party leader Nigel Farage said the efforts so far were an 'embarrassment'.
Scottish entrepreneur Duncan Bannatyne told MailOnline the government's 'dismal' handling of the testing crisis will send vast numbers of British businesses to the wall - and delay the country's economic recovery.
Experts have insisted 'organisation' rather than a shortage of facilities is to blame for the painfully slow rise in checks.
However, there are also suggestions that the UK is struggling to obtain enough of the tests themselves, with Germany seemingly able to acquire them from domestic manufacturers while Britain is having to import them.
It came amid reports that NHS England and NHS Wales ended up bidding against each other for testing equipment at the end of last week, prompting the four Home Nations to agree that all procurement will be done in Whitehall.
Germany has been conducting 500,000 tests a week and is aiming to hit 200,000 tests a day in the near future.
Part of the difference between the UK and Germany is reportedly that the latter has more tests available domestically.
There are also claims that a shipment of testing kit parts from the European mainland has been found to be contaminated with the virus, in another potential delay.
A nurse takes a swab from an NHS worker at a testing facility in Chessington yesterday
Germany is set to start mass immunity testing within weeks
Germany has also been leading the way on testing for individuals who have already been through the virus and emerged with immunity. Such checks could potentially allow people to be issued with certificates saying they are safe to go back to work - easing the lockdown crippling the economy.
The UK government has ordered 17.5million 'antibody' tests, but they have yet to go through clinical trials and it is not clear when they can start being used.
A study due to start in Germany in mid-April will see the blood of more than 100,000 volunteers tested for Covid-19 antibodies.
The process will be repeated at regular intervals, with the sample scaling up to track the progress of the epidemic.
Shadow health secretary Jon Ashworth said: 'Germany appears to be leading the way in the testing and we have much to learn from their approach.
'I've repeatedly called for more testing and contact tracing in the UK, and we should be looking at initiatives like this closely.'
Transport Secretary Grant Shapps admitted this morning that the government was struggling with the logistical challenge of increasing testing, saying it was not a 'trivial or straightforward' task.
'This is never going to be enough,' he told BBC Radio 4's Today programme. We always need to be pushing.'
Ministers boasted on Sunday that they had reached a target of 10,000 tests a day.
However, while the capacity has been reached, the government has yet to actually carry out that number. The latest figures from Public Health England were 8,278 in the 24 hours to 9am on Sunday, which was actually down from 9,114 the previous day.
The numbers have sparked widespread concerns about the UK approach to testing.
Mr Hunt, the chairman of the Health Select Committee, said it would be 'very worrying' if the UK chose not to follow the lead of the likes of Germany and South Korea.
He said mass testing allows for 'a lot less' disruption to daily lives because those who have the disease can be isolated and prevented from passing the virus on.
He said: 'It is internationally proven as the most effective way of breaking the chain of transmission.
'So however difficult it is to source the reagents, to ramp up the capacity of laboratories up and down the country, it is essential that mass community testing is part of our national strategy.'
Mr Farage told MailOnline: 'Testing is a catastrophe. It's an embarrassment. We do not appear to have done anything in six weeks to get ourselves in a better position on this.
'If I was an NHS frontline worker waiting week after week after week for this I would be furious.'
He added: '70,000 tests a day in Germany, a million tests now conducted in America, and we in six weeks have managed to do as many tests as the Germans do in two days.
'Everybody wants to believe in their leader during a crisis and everyone has given Boris the benefit of the doubt… I think public opinion is beginning to ask very serious questions.'
Scottish entrepreneur Duncan Bannatyne told MailOnline that the government's 'dismal' handling of the testing crisis will send vast numbers of British businesses to the wall - and delay the country's economic recovery.
The gym mogul and former Dragons' Den star said: 'The Government must get on top of testing immediately. The longer we are in lockdown the more businesses will go bust.
'My business hands over £39million to the Government every year in VAT, PAYE and corporation tax. As long as we are closed they get nothing. Their handling of the testing issue has been dismal to say the least.'
UK labs 'can't cope' with mass coronavirus testing, meaning millions of British-made swabbing kits are being sold OVERSEAS
By Matt Oliver for the Daily Mail
A British firm producing millions of pounds worth of coronavirus tests is selling most of them abroad as the UK doesn't have enough laboratories to use them.
Novacyt has made £17.8million selling its testing equipment to more than 80 countries via its Southampton-based subsidiary Primerdesign.
But only £1million worth has been sold to the UK, raising questions about why Britain is not buying more at a time when there are global shortages of tests.
When asked why the UK had not bought more kits and ramped up testing more quickly, Novacyt group marketing manager Achilleas Neophytou claimed UK laboratory capacity was a 'limiting factor'.
Pictured: A driver is tested at Chessington testing centre on Monday as the pandemic continues
This included staff available to carry out testing as well as the need for chemicals, he said. But last night a Public Health England (PHE) spokesman claimed Novacyt was not providing more tests because it was 'not able to offer the guaranteed continuity of supply we were looking for'.
Ministers are battling to increase testing to 25,000 patients per day by mid-April, but figures remained below 10,000 per day last weekend.
Mr Neophytou said: 'Even if we delivered ten times the number of kits to the Government, the limiting factor is still capacity of testing and that comes more and more under strain if laboratory staff go into self-isolation.
'A huge lab could also be brought below capacity if you do not have the consumables and instruments you need to run the tests.
'We are supplying 21 hospitals in the UK. Some of those serve other hospitals across the country. Some do not have the internal capacity to do these tests.
'So the number of testing kits is not truly representative of what the actual testing capacity of the country is at the moment.'
Novacyt said it is currently supplying 21 NHS hospitals with Covid-19 tests, which are processed by experts in labs.
It is in discussions with PHE about providing more tests, Mr Neophytou said. However, orders for its kit – which can return test results in two hours – have surged internationally, with regulators in the US, Argentina, the Philippines and Indonesia all fast-tracking the product for use by medical professionals.
Novacyt said it has sold £1.4million worth of tests to India alone, while countries in the Middle East have bought another £1.6million worth.
It is ramping up production with the help of Manchester-based Yourgene and says it will soon be capable of producing four million tests per month.
Novacyt is one of several organisations working with health authorities to roll out wider testing for the coronavirus.
Last week the Government said it was also working with dozens of universities, research institutes and companies to create three new 'hub laboratories' to supplement testing already being carried out.
Test makers Randox and Thermo Fisher are involved in these efforts, as well as Amazon, Royal Mail, Boots and the Wellcome Trust.
Universities have donated testing machines and volunteered staff to work in the new facilities, with hopes it will help ramp up the UK testing regime.
There are separate efforts as well to develop so-called rapid tests that do not need to be carried out in laboratories, although PHE is still reviewing these and has not yet recommended them for widespread use.
The World Health Organisation has called on countries to 'test, test, test', saying it is the best way to track the coronavirus outbreak and help bring down infection rates.
Cabinet office minister Michael Gove said the Government was increasing the amount of testing.
But during a daily Press conference, he admitted: 'One of the constraints on our capacity to increase testing overall is the supply of the specific reagents, the specific chemicals that are needed in order to make sure that tests are reliable.'
Last night the Department of Health suggested the tests provided by Novacyt were not as efficient as those being offered by other companies.
They also claimed that the tests wouldn't avoid the issue of the shortage of chemical reagents, as highlighted by the Government.