Halting all lockdown rules before May could lead to a disastrous new wave of Covid that almost doubled the death toll, scientific modelling has suggested.
An analysis for the government estimates 91,300 more people could die with coronavirus between last week and June 2022 if all rules were to lift on April 26.
The Warwick University study put the estimate of the number of extra deaths between 52,500 and 146,400 due to the level of uncertainty.
The scientists said almost 60,000 people could be in hospital at the same time in such a scenario – more even than in the second wave.
Scientists modelled six speeds for easing lockdown and ended up with more than 30,000 extra deaths in every one.
But the “very fast” scenario of ending all rules by April 26 was more dramatic.
By comparison, a more cautious unlocking between now and July could end up with 54,800 further deaths, a range of 32,600 to 82,900, the modelling suggested.
Just over 120,000 people so far in the UK have died within 28 days of a positive Covid test.
The analysis comes weeks after Tory MPs on the Covid Recovery Group demanded all restrictions were lifted by April 30.
The MPS argued there would be no justification for legal restrictions because all over-50s and other priority groups would have had their first dose of the vaccine.
But Sir Patrick Vallance warned “a large number of people in the population remain unprotected” even with high take-up of the vaccine.
The Chief Scientific Advisor explained: “Let’s say 80% of people are adults, so 20% of people are not being vaccinated even if you got to all of the adults, and you get roughly an 80% vaccine efficacy, and that gives roughly 80% protection – you’ve got roughly 50% across the whole population.
“That tells you that even at quite high levels of coverage and protection, you’ve still got a large number of people who are unprotected.”
Scientists from Warwick University and Imperial College London modelled six different speeds out of lockdown and looked at how they would affect hospitalisations and deaths for the Scientific Pandemic Influenza Group on Modelling (SPI-M).
Those were a “very fast”, “fast”, “medium” and “gradual” unlocking, as well as two “new” scenarios labelled 5a and 5b with different timings.
Warwick University’s study said bluntly: “All of the relaxation scenarios lead to a third wave of infections.”
The harshest “very fast” scenario would lift all measures by April 26. The “fast” scenario would lift all measures by May 31, while the “gradual” scenario would lift them by August 2.
Even in the “gradual” scenario, the scientists modelled there could be 58,200 extra deaths between 12 February 2021 and 30 June 2022 – a range of 31,000 to 95,300.
The estimates varied dramatically depending on effectiveness of the vaccine, remaining lockdown measures and other factors.
They were even higher in a scenario where the vaccine is less effective, for example.
Labour deputy leader Angela Rayner said: “It is deeply concerning that a group of Conservative MPs is actively campaigning for a policy that the government’s own scientific advisers warn could lead to a deadly fourth wave, a 50 per cent spike in the death toll and up to 100,000 more deaths.”
She accused the PM of “reckless incompetence” in handling the pandemic.
Ms Rayner added: “If we are to ensure this is our last lockdown, he must now face down those Conservative MPs who have throughout this crisis undermined the national effort to defeat the virus.”
Boris Johnson’s roadmap today suggests all legal restrictions could be lifted by June 21 at the earliest.
But it cannot be compared directly to the modelling for SAGE, because the Prime Minister has left some issues up in the air.
Social distancing rules, mask wearing and hand-washing could continue beyond June 21 if a review recommends they continue.