Boris Johnson has said he "can't rule out" plunging the nation into another lockdown if a more deadly Covid variant emerges.
The Prime Minister said he wouldn't take "any options off the table" but said sweeping restrictions were unlikely as the virus was "losing its potency".
An estimated 4.1 million people had Covid in England in the week to April 2 - around one in 13 people - according to figures from the Office for National Statistics.
The number of people in hospital in England has also hit the highest level since January 2021 and has now surpassed the peak of the Omicron wave at the start of this year.
But symptoms are generally less severe than previous variants.
The Prime Minister was pressed on the likelihood of fresh restrictions in an interview with GB News.
Bizarrely the interview was conducted by two of his own Tory MPs, Esther McVey and Philip Davies, who present a show on the channel and have secured regular interviews with ministers from their own party.
He said: "I want to avoid any such thing ever happening again. I can't rule out, I can't say we wouldn't be forced to do non-pharmaceutical interventions again of the kind we did.
"I think it would be irresponsible of any leader, in any democracy, to say they are going to rule out something that could save life.
"I believe that the things that we did saved lives."
Mr Johnson warned there could be a new variant that was more deadly or that affected children badly that needed to be contained.
"I'm not going to take any options off the table but I don't think it will happen," he said.
"We are now in the phase where the virus is losing its potency overall and we've got a massively vaccinated UK population."
Mr Johnson resisted imposing a national shutdown as Omicron cases surged in December and January, amid pressure from lockdown-sceptic Tories.
He told MPs in January that the Government "does not believe we need to shut down our country again", instead focusing on the rapid expansion of the booster scheme.
The overall Covid-19 hospital admission rate for England hit 20.5 per 100,000 people in the week ending April 3, according to recent figures from the UK Health Security Agency.
It marked the fifth successive weekly increase and means total admissions are now at a higher rate than at the peak of the original Omicron wave at the start of January this year (19.9).
But the rate is still some way below the all-time high of 36 per 100,000 in the first week of January 2021.
