The prime minister has hailed the "courage, discipline and patience of the nation" one year after he first announced a lockdown to combat the coronavirus pandemic.
Speaking at a Downing Street news conference, Boris Johnson said: "We suffered so many losses."
And he said we have at times been "fighting in the dark" against a "callous" enemy but science has helped us "turn the lights on".
He also said after an "epic of endurance and privations" that "we did it – together".
In answer to a question from Sky News’ Beth Rigby about what the legacy of the pandemic will be, Mr Johnson said the focus must be on education and "remediating the damage, plugging the gaps".
He said that the "future of the country depends on us now repaying that generation" of schoolchildren and students.
And the PM acknowledged: "I certainly think that this is something that we will all remember and be dealing with in different ways for probably – certainly in my case – for as long as I live."
Leading the 145th Number 10 briefing of the pandemic, Mr Johnson inevitably faced questions about what the government could – and critics would content should – have done differently.
"In retrospect there are probably many things that we wish that we’d known and many things that we wish we’d done differently at the time, in retrospect, because we were fighting a novel disease under very different circumstances than any previous government had imagined," the PM said.
He said the "biggest false assumption" was over the scale of asymptomatic transmission of COVID.
And Mr Johnson defended the government against accusations it was too slow in introducing the lockdowns, saying: "We took all the decisions with the interest of the British people foremost in our hearts and in an effort to protect the public and prevent death and suffering."
Sir Patrick Vallance, the government’s chief scientific adviser, said greater testing capacity in the early days of the pandemic would have made a "big difference".
Mr Johnson said that after a year that has seen three lockdowns and restrictions affecting numerous elements of everyday life, the UK was "cautiously but irreversibly, step by step, jab by jab" on the way to "reclaiming our freedoms".
He promised that "at the right moment" a permanent memorial to those who have died will be built and the "whole period" will be remembered.
It was a year ago to the day, that Mr Johnson told the country: "From this evening I must give the British people a very simple instruction – you must stay at home."
The PM’s comments come after people across the UK observed a minute’s silence to remember the victims of the coronavirus pandemic.
At 8pm people are being encouraged to stand on doorsteps with phones, candles and torches to signify a "beacon of remembrance".
The London Eye, Tate Britain, Blackpool Tower, the Scottish Parliament, Belfast City Hall and other landmarks will be lit in yellow on Tuesday evening to mark the occasion.
Having introduced a third national shutdown in January, Mr Johnson begun easing restrictions earlier this month with the full reopening of primary and secondary schools.
But he repeated his warning about the potential effects of a third coronavirus wave in Europe, saying the UK has to be "very wary".