Boris Johnson "can't count on Labour support" to end self isolation rules unless he provides scientific backing for it, a frontbencher has said.
Shadow Health Secretary Wes Streeting accused the Prime Minister of trying to "declare victory before the war is over" with the virus in the hope of overshadowing the Partygate row.
Mr Johnson is expected to tell MPs tomorrow he will rip up self isolation requirements for people with Covid this week, as part of a plan to repeal all pandemic regulations in England.
Mr Streeting said he was "very worried" by plans to end free access to testing - adding: "It's a bit like being 2-1 up with 10 minutes left of play and taking your best defender off the pitch."
Asked if Labour supported the decision to end legal self isolation, Mr Streeting told BBC's Sunday Morning: "At this stage the PM risks muddying the waters.
"We want to see the Government publish the scientific advice because at the moment this seems very premature.
"It seems like Boris Johnson is keen to declare victory before the war is over in the hope he gets some headlines about 'victory day on Covid' instead police officers asking questions about actions in No 10."
He said Labour's position had always been to support the science - and demanded answers on what the experts think on the plan.
"If he is deviating from scientific advice then he can't count on Labour support," Mr Streeting said.
It comes as a SAGE expert raised concerns that it was too early for the scrapping of self-isolation rules and free Covid-19 testing.
Dr Mike Tildesley, a member of the Scientific Pandemic Influenza Modelling group (Spi-M), told Times Radio that at some point the restrictions would have to be eased but that "the concern now is that we still have relatively high cases".
"The concern, of course, is with removing testing, removing self-isolation, that may cause quite a big change in behaviour."
He warned said one of his biggest concerns was support for people in low-income jobs to isolate and that there was a "real concern" that getting rid of the rules would lead to more infections in workplaces.
"If we lose free testing then a lot of people won't test any more and without that data that will put us in a much weaker position," he added.
He said that "in the longer term" we would have to move to a post-Covid phase, but "in the short term we're not out of the woods yet".
Dr Chaand Nagpaul, the chair of the Council of the British Medical Association, said it was too early as more people were dying and in hospital than when plan B measures were introduced.
He told the BBC: "It seems a rather odd decision to make.
"We need to see case rates fall down even more remembering that people aren't being restricted at the moment in any severe way at all - people are living normally.
"The second thing is we do need therefore to continue having surveillance because you won't know whether you've reached that point where the infection rates have come down enough until you've had that surveillance."
But Mr Johnson said it was time to move away from strict curbs as he prepares to announce his new 'Living with Covid' strategy on Monday.
"We have reached a stage where we think you can shift the balance away from state mandation, away from banning certain courses of action, and compelling certain courses of action, in favour of encouraging personal responsibility," he said.
"I think it's very important we should remain careful," he said.
"We're certainly not asking people to throw caution to the winds. Covid remains a dangerous disease, particularly if you haven't been vaccinated."
He refused to rule out reintroducing lockdown restrictions if there was a new variant, adding: "You've got to be humble in the face of nature."
But he said the UK cannot continue to spend £2 billion a month on testing.
"I think we need resilience, but we don't need to keep focused on testing," he said.
"We don't need to keep spending at a rate of £2 billion a month - which is what we were doing in January."
