The UK has reported no deaths from Covid in a day, for the first time in 10 months, raising optimism in Downing Street that England could forge ahead with the final stage of the roadmap despite scientists warning that extra restrictions might be needed to control a third wave.

Matt Hancock, the health secretary, hailed the statistic as proof that vaccines were breaking the link between infection and severe illness, though scientists warned against reading too much into the numbers following a bank holiday weekend.

Official figures on Tuesday showed the four nations of the UK recorded no new deaths within 28 days of a positive Covid test, for the first time since July 2020.

Due to delays in recording deaths, however, it will take time before statisticians know for sure whether there were zero deaths from coronavirus on Monday. In January, at the height of the pandemic, 1,820 deaths were recorded on a single day.

Government sources suggested the prime minister, Boris Johnson, was still minded to lift the social restrictions on 21 June, despite warnings from scientific advisers that the UK was embarking on a third wave, with infection rates rising.

No 10 suggested there was not yet conclusive evidence to suggest that the infection rates would lead to a surge in hospitalisations, which might overwhelm the NHS or cause many more deaths.