Coronavirus infections have finally started falling according to the biggest national swab testing survey.

The REACT study by Ipsos Mori and Imperial College London took 168,000 swabs and identified a fall from January 15 to 22.

Its latest two-week snapshot of infections in England put the R value at 0.98 for the full period from January 6 to 22.

It comes as the Welsh government announced that its reproductive range - the average number of people each case infects - was between 0.7 and 0.9.

The data suggests the devastating winter surge in infections could finally be shrinking, however England’s average is driven by falling rates in the south.

Sir Patrick Vallance told the Downing Street briefing: “We are at a position where the lockdowns have worked.

Britain's Chief Scientific Adviser Patrick Vallance
Britain's Chief Scientific Adviser Patrick Vallance speaks during a virtual press conference on the Covid-19 pandemic

“They’ve slowed this down, they reached a position where it’s reached a plateau and is beginning to decline.

“We see that in cases, we’re beginning to see it in hospital admissions, and we’re beginning to see it in deaths.

“But it’s early days and this isn’t coming down quickly. We remain at very high levels and it’s going to take weeks for this to start to come down to really low levels.”

Scientists behind the REACT study warned the fall in England as a whole is happening much slower than at the end of the first lockdown.

REACT director Prof Paul Elliott, of Imperial, said: “We are definitely heartened by the fact that we’re now seeing what looks like a decline in the last week of our survey.

“Even though we’re seeing this suggestion of a downtick now, which is really good news, it’s by no means as fast as we saw in lockdown one.

“It’s going in the right direction, probably, but it’s not going in the right direction fast enough.”

Covid-19 vaccinations being given at the Peepul Centre
Covid-19 vaccinations being given at the Peepul Centre, Belgrave, Leicester

The fall in the national average was being driven by dropping infections in London, the South East and the South West.

The data suggested cases were still rising in the East Midlands and the North East, but were flatlining in Eastern England, the West Midlands, Yorkshire and the Humber.

Overall in England during the latest round of REACT one in every 64 people had Covid-19.

Health Secretary Matt Hancock said: “These findings are a stark reminder of the need to remain vigilant.

“Infection rates this high will continue to put a strain on our NHS and add to the significant pressures dedicated health and care staff are already facing.

“We must bring infections right down so I urge everyone to play their part to help save lives.

“You must stay at home unless absolutely necessary, follow social distancing rules and minimise contact with others.”

Two men socially distance as they meet in a street in Cwmbran centre
The public have been urged to social distance

Regional prevalence was still highest in London at 2.83% followed by the East of England at 1.78%, the West Midlands at 1.66% then the South East region at 1.61%.

The North West recorded 1.38% of its population with the virus, the North East at 1.22%, the East Midlands at 1.16%, Yorkshire and The Humber 0.80%, and finally the South West at 0.87%

Dr Frank Atherton, the chief medical officer for Wales, told the Welsh Government briefing that the R value was now below 1.

He said the rate of infection currently was around 200 per 100,000 people, which was a third of what it was two weeks before Christmas when rates were around 650 per 100,000 but still “way too high”.

Dr Atherton was questioned at what level the R number would have to be and at what level the rates of infection would be before schools could reopen and restrictions eased.

“It is quite a complex equation and I don’t think there is an absolute cut-off that I would point to when we can start to reopen things,” he said.

“We need to learn from what happened when we came out of previous lockdowns - the first lockdown in March, the firebreak in November.

“What we saw there was even though rates had come down quite well when we released things, we released them in a way which allowed the virus to re-establish itself very, very quickly.”