Lockdown easing may have to be reversed if Covid-19 variants spread quickly, government scientists have warned.
Professor Peter Openshaw said his fellow scientists were “very concerned” after a cluster of cases of the South African coronavirus variant were found in London.
And vaccine chief Professor Anthony Harnden said scenes of people crowded outside pubs as restrictions began to ease would “push infection rates up.”
Some 44 confirmed cases of the variant have been found in Lambeth and Wandsworth, with a further 30 probable cases identified, the Department of Health and Social Care (DHSC) said.
Surge testing for those who live, work or travel through those areas is being made available, while NHS Test and Trace is providing additional testing in an area of Southwark where a case linked to the other cluster has been identified.
Prof Openshaw, a member of the Covid-19 clinical information network, told BBC2’s Newsnight: “A lot of we scientists are very concerned about what’s happening at the moment.
“I think we’re all just hoping that the staged reduction in lockdown is going to be ok. It is being done reasonably cautiously but I think this is not good news.
“If we get rapid spread of the South African or other more resistant variants, it may well be that we are going to have to put the reductions of lockdown into reverse.”
Professor Harnden, deputy chairman of the Joint Committee on Vaccination and Immunisation (JCVI) said Boris Johnson was right to remind Brits that both lockdown and vaccines had been important in reducing hospital admissions and deaths.
He told BBC Breakfast: “And I think he’s probably concerned, as I am, about the scenes in London that we saw of people actually enjoying the outside, pubs and then the crowded spaces – well, of course what that will do is push infection rates up.
“Every time that we ‘unlockdown’, we push infection rates up, and the danger of pushing infection rates up is we get much more transmission in the community.
“And new variant strains such as the South African strain – we really don’t want that to become prevalent in this country because of course the vaccines don’t work quite as well (against it).
“So I think he’s trying to be cautious with everybody. We will all want to get our lives back, we all want to enjoy ourselves again, but we must be cautious and do this slowly. Otherwise we’ll get back to square one.”
He added: “We don’t need to behave in exactly the same way that we behaved before this pandemic because if we’re just that little bit more cautious, just give it a little bit more time to get the complete population vaccinated, get infection rates down, we will be in a lot better place.
“Of course we can enjoy ourselves, but we just need to maintain that social distancing at the moment.”
According to Government figures, there have been 533 genomically confirmed cases of the South African variant in the UK and another 11 probable cases.
Lockdown was further eased in England on Monday, with non-essential retail and pub beer gardens permitted to open, and Prime Minister Boris Johnson said there were no plans at present to change the road map out of lockdown.
The next “waymarks” on England’s plan to ease restrictions are due on May 17 and June 21.