Ministerial appointments are expected to follow soon after an acceptance speech in Downing Street.
Britain's main opposition Labour party looks set for a landslide election win, exit polls indicated on Thursday, with Keir Starmer replacing Rishi Sunak as prime minister, ending 14 years of Conservative rule.
The survey for UK broadcasters suggested centre-left Labour would win 410 seats in the 650-seat House of Commons, with the right-wing Tories managing only 131 -- a record low.
In another boost for the centrists, the smaller opposition Liberal Democrats would get 61 seats, ousting the Scottish National Party on 10 as the third biggest party.
Nigel Farage's hard-right anti-immigration Reform UK party could secure 13, with Welsh nationalists Plaid Cymru four and the Greens doubling their MPs to two.
Labour's majority would be 170 -- more than double than that won by Boris Johnson for the Tories at the last election in December 2019 dominated by Brexit.
"To everyone who has campaigned for Labour in this election, to everyone who voted for us and put their trust in our changed Labour Party -- thank you," Starmer wrote on social media.
Outside Starmer's local pub The Pineapple in north London, pub-goers called the expected result "a new dawn" but there were no wild celebrations.
Starmer's deputy, Angela Rayner, told the BBC the numbers were "encouraging... but I'm not counting my chickens until we've got those results coming in".
Former Conservative leader William Hague told Times Radio the projected result would be "a catastrophic result in historic terms" for the Tories.
The Tories worst previous result is 156 seats in 1906.
But Tim Bale, politics professor at Queen Mary, University of London, said it was "not as catastrophic as some were predicting" and the Tories, riven by ideological infighting, needed now to decide which direction they would take.
'Brighter future'
Counting of ballots from some 40,000 polling stations across the country stretches into the night, with official results expected into Friday morning.
The first to declare, just over an hour after polls closed at 2100 GMT, was Houghton and Sunderland South, in northeast England, where Labour's Bridget Phillipson was returned as MP.
Phillipson, nailed on to become education secretary, said in an acceptance speech that Britons seemed to have chosen a "brighter future".
"After 14 years the British people have voted change... Labour will honour the trust that you have placed in us," she told supporters to applause.
The projected overall result bucks a rightward trend among Britain's closest Western allies, with the far-right in France eyeing power and Donald Trump looking set for a return in the United States.
Under Britain's first-past-the-post electoral system, a party needs 326 seats to win an overall majority in parliament.
The leader of the winning party is expected to meet head of state King Charles III on Friday morning, who will ask the leader of the largest party to form a government.
Ministerial appointments are expected to follow soon after an acceptance speech in Downing Street.
To-do list
Confirmation of the result would cap a remarkable rise to power for Starmer, 61, who was first elected as a member of parliament in 2015 -- and a stunning turnaround for Labour.
The former human rights lawyer and chief public prosecutor was elected Labour leader in early 2020, succeeding the veteran leftist Jeremy Corbyn, who lost by a landslide to Johnson in 2019 -- Labour's worst performance since 1935.
Starmer has since dragged the party back to the centre ground, making it a more electable proposition and purging infighting with the hard-left and anti-Semitism that lost it support.
Opinion polls have given Labour a consistent 20-point lead over the Tories for almost the past two years, which a largely lacklustre election campaign has failed to change.
Some polls predicted a virtual wipe-out for the Tories, given negative public opinion and the arrival of Reform UK to split the right-wing vote.
That gave an air of inevitability about a Labour win -- the first since Tony Blair in 2005 -- which the party feared could hit turn-out.
Starmer -- the working-class son of a toolmaker and a nurse -- has promised "a decade of national renewal" after post-financial crash austerity measures, Brexit upheaval and a cost-of-living crisis.
But his to-do list is daunting, with economic growth anaemic, public services overstretched and underfunded due to nearly a decade-and-a-half of swingeing cuts, and households squeezed financially.
The Labour leader has also promised a return of political integrity, after a chaotic period of five Tory prime ministers, including three in four months, scandal and sleaze.
His first days in office are set to be packed, representing Britain at the NATO conference in Washington next week, then hosting European leaders later this month at a summit in southern England.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)