OVER-40s will get their second Covid vaccine sooner - to beat the Delta variant.
Boris Johnson this evening announced England is following Scotland's lead and lowering the age of Brits allowed to book in earlier to be fully protected.
🔵 Read our coronavirus live blog for the latest updates
It comes as the Prime Minister confirmed June 21 won't be the hoped for "Freedom Day".
This is due to rapidly rising cases of the Delta variant, first identified in India, and an increase of hospitalisations.
He said: "We can simply keep going with all of Step 4 on June 21, even though there is a real possibility that the virus will outrun the vaccines and that thousands more deaths would ensue which could otherwise have been avoided.
"Or else we can give the NHS a few more crucial weeks to get those remaining jabs into the arms of those who need them.
"And since today I cannot say that that we have met all our four tests for proceeding with Step 4 on June 21, I think it is sensible to wait just a little longer.
He added that by July 19 around two-thirds of the adult population would have received two jabs, including all over-50s, the vulnerable and health and care workers, along with over-40s who had received a first dose by mid-May.
"To do this we will now accelerate the second jabs for those over 40, just as we did for the vulnerable groups, so they get the maximum protection as fast as possible.
"We will bring forward our target to give every adult in this country a first dose by July 19."
Up until today only those over-50 in England were able to have their second vaccine eight weeks after the first.
Anyone younger has to wait around 12 weeks to get their full vaccination.
But earlier today ministers hinted earlier the age bracket of those eligible for a speedier second dose would be lowered.
'GIVE THE VACCINES EXTRA LEGS'
Experts said this would "make sense", with Professor Anthony Harnden telling the BBC's Radio 4 Today programme: "As we move down the age groups, particularly with plentiful supply of AstraZeneca vaccine, it would make sense to shorten that dose interval from 12 to eight weeks."
He added the JCVI is "looking carefully at what the Scottish Government has done", adding "it seems to be a sensible strategy".
Sir Stephen Vallance, addressing the country alongside Prof Whitty and the PM on Monday evening, said "these vaccines are really highly effective against the Delta variants".
And by delaying the full unlocking to July 19 an extra 10 million second Covid vaccine doses can be administered - protecting more of the nation.
On Sunday, Dominic Raab, the Foreign Secretary, told the Andrew Marr programme the country was in a "race" to "get everyone to two doses".
"If that is the scientific advice, of course we will look at it very carefully - but at the moment the advice we are getting is the approach that we are following, which is the over-50s, and we have got the supplies to do that."
He indicated the government wants to use the additional time to get millions more younger people double-jabbed.
The cautious approach was, he said, necessary to ensure the the unlocking was "irreversible" and that they did not have to "yo-yo back in and out of measures".
This weekend, the Prime Minister told ITV News: "We're looking at all the data but what we're wanting to do is avoid another wave of deaths that could be prevented by allowing the vaccines to work in the way that they are.
"It may be that in the race between the vaccines and the virus, we need to make sure we give the vaccines extra legs."
The latest daily Government figures from Sunday showed another rise in infections with a further 7,490 lab-confirmed cases in the UK - up 2,149 from a figure of 5,341 the previous week.
The data also had England with a total of 35,971 positive tests in the past seven days at a rate of 63.9 per 100,000 people.
In Scotland People over 40 whose second coronavirus vaccine dose is more than eight weeks after their first are being encouraged to seek an earlier slot.
Health Secretary Humza Yousaf said: "We are working closely with NHS boards to ensure the number of appointments can be increased in line with national guidance to help combat new variants and provide protection to as many people as possible.
"Boards are boosting their capacity to administer second doses alongside the delivery of first doses to younger cohorts and appointments are now being issued in accordance with the new recommendation of an eight-week gap.
"The second dose is vital in providing greater and longer lasting protection against the virus - particularly the new Delta (Indian) variant.
"In line with the advice from the JCVI, we encourage those whose appointment was already scheduled - which is mainly over-40s at this time - to use the NHS Inform online tool, drop-in clinics or the national helpline to get their second dose appointment as close to eight weeks after their first as possible."
We're looking at all the data but what we're wanting to do is avoid another wave of deaths that could be prevented by allowing the vaccines to work in the way that they are.Boris Johnson
Prof Mark Woolhouse, Professor of Infectious Disease Epidemiology, University of Edinburgh, said: “First, a delay would provide time to increase the proportion of UK adults who have received both doses of vaccine. This is important because the second dose significantly increases levels of protection against the delta variant.
“Second, a delay would give more time to fully assess the potential of the delta variant to cause a serious public health problem that could overwhelm the NHS.
"This could happen because a large wave of infection (mainly in younger adults who have still not been vaccinated) would inevitably spill over to the small percentage of vulnerable people who have not been vaccinated and to vulnerable people who have been vaccinated (for whom the vaccines gives high protection but not 100 per cent).!
The potential month-long delay means pubs will be restricted to table service, with the return of propping up the bar still some way off.
Theatres and cinemas will continue to be capped at just 50 per cent capacity, and people will be told to continue working from home if they can.
Nightclubs - many of which have been closed since the start of the pandemic - will remain closed.
COVID BLOW Watch LIVE as Boris Johnson delays June 21 lockdown lift for at least 4 weeks
DOUBLE DOSETwo Covid jabs STOP hospitalisation from Delta variant in ‘up to 96% of cases’
VIRAL LOADMaps reveal how fast Delta strain has spread in weeks - and areas it's dominant
VIRAL LOADBrits in six areas hit with new Covid travel rules to stop Delta variant spread
FEEL THE STRAINDelta variant 'DOUBLES risk of ending up in hospital but jabs do protect
And gigs will also take a hit, as the current rules allow for capacity limits of 50 per cent - or a maximum of 1,000 people - indoors.
Outdoor gatherings will remain limited to 30 people, meaning summer BBQs and picnics in the park will have to stay small.
The rule of six will stick around for indoor meet-ups, while face masks and social distancing will continue to be enforced.