The conservative government of British Prime Minister David Cameron is on track to lead Britain for another five years.
An exit poll by the BBC says the Conservatives (also known as Tories) could win a majority 326 of 650 seats in the lower house of Parliament, or House of Commons.
News reports say Cameron was scheduled to meet later on May 8 with Queen Elizabeth. Visiting the monarch is a formality required to form a government.
A Cameron victory would mean Britain is likely to face a historic in-out European Union referendum within two years, fulfilling a key campaign pledge.
Poll projections suggest the opposition Labour Party suffered a stinging disappointment, winning only 239 seats despite predictions of a much closer race.
"Obviously, it's a very, very clear victory for the Conservatives, and a very bad night for Labour," if the exit poll is accurate, said London Mayor Boris Johnson, who ran for a seat in Parliament as a Conservative.
The shortfall for Labour was largely due to a rout in Scotland, where Nationalists unseated previously dominant Labour legislators and took all but one of Scotland's 59 seats in the House of Commons.
Liberal Democrats also took a drubbing, with their share of seats shrinking from 56 to 10.
The decline of Labour and the Liberals reflected the ascendance of once-minor parties, particularly the rise of the Scottish Nationalist Party from two to 58 seats.
Capping the astonishing rise of Scotland's separatist party, which was particularly popular among younger voters, a 20-year old student there was elected Britain's youngest lawmaker since 1667. Mhairi Black took the Paisley seat of one of Labour's top figures, election campaign chief Douglas Alexander.
The landslide win for the Nationalists raised the odds that Scotland will schedule a new referendum on independence after the narrow loss of a vote on the matter last year.
Opposition politicians urged caution about jumping to conclusions, noting that while the BBC exit poll has had a good track record of predicting winners in past elections, the large number of parties competing this time has raised the potential for error. Final results will be announced on May 8.
"I have to say it just doesn't feel right," said longtime Labour adviser Alistair Campbell.
Former Liberal Democrat leader Paddy Ashdown was equally skeptical, telling the BBC: "I'll bet you my hat, eaten on your program, that it is wrong."
The chief exit pollster, John Curtice of Strathclyde University, said the methodology was the same as in 2010, when the poll turned out to be very accurate.
He said it looked as if Conservative and Labour gains had canceled each other out across England and Wales, and that Labour had lost much of its support in Scotland due to the meteoric rise of the Scottish Nationalist Party.
Curtice said early vote tallies were "in line with the exit poll," adding that an outright Conservative majority couldn't be ruled out.
Analysts attributed the disparity with polls taken before the election, which predicted a close outcome between Conservatives and Labour, to a phenomenon in England where voters have been "shy" about identifying with the party of austerity, which has imposed harsh budget cuts in recent years.
"Shy" voters who secretly sided with Conservatives helped John Major win the 1992 general election even though opinion polls had indicated Labour was ahead.
Sunny weather in many areas boosted turnout to more than 70 per cent of eligible voters, with a higher figure of about 75 per cent in Scotland, pollsters said.