Final lockdown lifting on June 21 has again been thrown into doubt as scientific experts warned it was “too early to be charging ahead” with the plans.
Fears over the spread of the Indian variant and hospitals coming under pressure risk delaying the official roadmap.
Ministers are understood to be drawing up plans for a partial end to the lockdown, despite the government previously hoping to end all legal restrictions from June 21 at the earliest.
The roadmap would potentially allow parties of hundreds of people and the reopening of nightclubs in just a few weeks’ time.
But vaccines minister Nadhim Zahawi warned the Government would have to be “cautious” in deciding whether it can press ahead with its relaxation of restrictions in England as planned.
“We have to be cautious. We have to look at the data and share it with the country,” he told the BBC.
“Are we still vaccinating at scale? Big tick. Are the vaccines working? Yes.
“But are infection rates too high for us to then not be able to proceed because there are too many people going into hospital? I don’t know the answer to that. We will know it hopefully on June 14.”
The continued spread of the Indian coronavirus variant has prompted experts to argue restrictions should remain in place until more people have received both doses of a vaccine.
Hospitals chief Chris Hopson called for a more informed debate on the planned lifting of all legal limits on social contact.
The NHS Providers chief executive said hospitals are currently coping with the strain of Covid but other people who put off treatment are now coming forward.
“We know this variant is much much more transmissible and lots more people still need a vaccination,” he told the BBC.
“We need a really good high quality debate about how quickly should we open up on June 21.”
A top Government scientist claimed there was still “an awful lot of uncertainty” over whether the June 21 date can go ahead.
Dr Mike Tildesley, a member of the Scientific Pandemic Influenza Group on Modelling (Spi-M) Government advisory panel, said: “I think at the moment there’s quite a lot of uncertainty around that.
“We are starting to see signs of course that cases are going up, but at the moment we’re still obviously reporting hospital admissions and deaths at very low levels.”
Prof Linda Bauld of Edinburgh University warned that the data and evidence did not support lifting the remaining lockdown restrictions on June 21.
“It is too early to be charging ahead,” she said. “I would like to see seven more weeks data and the kind of evidence I want to see, and all my colleagues, that the chains of transmission, the links between the fact that we had slightly more cases when we opened up but it is moving through the system to people who are becoming unwell.”
In his strongest attack for months on the PM’s handling of the pandemic, he said: “Weak, slow decisions on border policy let the Indian variant take hold,” he said.
“Lack of self-isolation support and confused local guidance failed to contain it.
“We all want to unlock on June 21 but the single biggest threat to that is the Government’s incompetence.”
Data suggests that although hospital admissions are rising in some parts of the country affected by the Indian variant, overall admissions remain broadly flat.
However, the “R” number for England is 1 to 1.1, up from 0.9 and 1.1 the previous week, suggesting the epidemic is growing.
One scientific adviser warned confusion over the Government’s handling of Covid restrictions was undermining efforts to control the virus.
Prof Stephen Reicher, who sits on a SAGE sub-committee, said the Government was in a “pickle” because it appeared to have abandoned the “data not dates” principle.