Rishi Sunak has apologised to the country and his party after he led the Conservatives to their worst-ever election result.
The outgoing Prime Minister added he will step down as Tory leader, but only once formal arrangements are in place to select his successor.
Former prime minister Liz Truss and a record number of serving Cabinet members lost their seats in the Tory bloodbath, as Labour swept to power under leader Sir Keir Starmer.
Speaking under grey skies and with his wife Akshata Murty watching on, Mr Sunak delivered his final Downing Street address before his premiership officially ends.
Mr Sunak said: “To the country, I would like to say first and foremost, I am sorry.
“I have given this job my all, but you have sent a clear signal that the Government of the United Kingdom must change. And yours is the only judgment that matters.
“I have heard your anger, your disappointment, and I take responsibility for this loss.”
Mr Sunak also apologised to Conservative candidates and campaigners, before saying: “Following this result I will step down as party leader – not immediately, but once the formal arrangements for selecting my successor are in place.
“It is important that after 14 years in government the Conservative Party rebuilds, but also that it takes up its crucial role in opposition professionally and effectively.”
Mr Sunak gave his thanks to his colleagues and staff before adding: “But, most of all, I’d like to express my gratitude to my wife Akshata and our beautiful daughters.
“I can never thank them enough for the sacrifices they have made so that I might serve our country.”
Mr Sunak praised Sir Keir as a “decent, public-spirited man who I respect” as he conceded defeat outside Number 10.
The Tory MP said “whatever our disagreements,” he wished Sir Keir and his family well as they make “the huge transition to their new lives behind this door”.
Mr Sunak, who was re-elected in Richmond and Northallerton, said: “In this job, his successes will be all our successes, and I wish him and his family well.”
He said he believes the UK is “more prosperous, fairer and resilient than it was in 2010” when the Conservatives came to power.
He concluded his farewell speech by acknowledging the “difficult days” of the election campaign and pointing to the British values of “kindness, decency and tolerance”.
Mr Sunak said: “One of the most remarkable things about Britain is just how unremarkable it is that two generations after my grandparents came here with little, I could become Prime Minister. And that I could watch my two young daughters light Diwali candles on the steps in Downing Street.
“We must hold true to that idea of who we are. That vision of kindness, decency and tolerance that has always been the British way.
“This is a difficult day at the end of a number of difficult days. But I leave this job honoured to have been your Prime Minister.
“This is the best country in the world. And it is thanks entirely to you, the British people, the true source of all our achievements, our strengths and our greatness. Thank you.”
Mr Sunak’s apology was earlier echoed by Suella Braverman, but the Tory leadership challenger was sorry for her party’s record in Government, suggesting it had not listened enough to the electorate.
Ms Truss lost her South West Norfolk seat, where she had been defending a notional majority of more than 24,000, to Labour.
The former prime minister, who during her short time in Downing Street oversaw the disastrous mini-budget that spooked markets, said the Tories had not “delivered sufficiently” on voters’ priorities including curbing immigration.
Ms Truss declined to give a concession speech but told the BBC: “I think the issue we faced as Conservatives is we haven’t delivered sufficiently on the policies people want.
“And that means keeping taxes low, but also particularly on reducing immigration.”
Asked whether she accepted some responsibility for that, Ms Truss said: “I agree. I was part of that. That’s absolutely true.
“But during our 14 years in power, unfortunately we did not do enough to take on the legacy we’d been left, in particular things like the Human Rights Act that made it very difficult for us to deport illegal immigrants.”
Meanwhile, former justice secretary Sir Robert Buckland warned that a lurch to the right would be “disastrous” for the party after he lost his Swindon South seat.
Among the dozen Cabinet ministers to lose their seats overnight were Commons Leader Penny Mordaunt, Defence Secretary Grant Shapps, Welsh Secretary David TC Davies, Transport Secretary Mark Harper, Attorney General Victoria Prentis and veterans minister Johnny Mercer, all to Labour.
Education Secretary Gillian Keegan, Justice Secretary Alex Chalk, Science Secretary Michelle Donelan, Culture Secretary Lucy Frazer and illegal immigration Minister Michael Tomlinson lost to the Liberal Democrats.
Chief whip Simon Hart lost to Plaid Cymru.
But party chairman Richard Holden won by just 20 votes in Basildon and Billericay and Jeremy Hunt clung on to the Godalming and Ash seat in Surrey despite a threat from the Liberal Democrats.
The outgoing Chancellor said the Conservatives’ “crushing” defeat was a “bitter pill to swallow” for the party.
Mel Stride, who served as Work and Pensions Secretary and held on to his Central Devon seat by just 61 votes, said it would take “quite a lot of time” for the Tory Party to “rebuild”.
Outgoing Home Secretary James Cleverly, who held his seat in Braintree, Essex, warned that “there is nothing honourable in presenting simple and thin solutions to challenging and complex problems”.
Mr Shapps, who lost his Welwyn Hatfield seat to Labour, said his party had an “inability to iron out (its) differences” amid an endless “soap opera”.
Seats previously held by Tory big beasts, including Boris Johnson’s Uxbridge and South Ruislip and Theresa May’s Maidenhead, were taken by Labour and the Liberal Democrats respectively.
Tory Northern Ireland minister Steve Baker, who had signalled his intention to launch a Tory leadership bid after the election, said “thank God I’m a free man” after he was defeated by Labour in Wycombe.
Tory deputy chairman Jonathan Gullis, former cabinet minister Sir Jacob Rees-Mogg and business and trade minister Greg Hands were beaten by Labour.