LONDON Three opinion polls on Wednesday predicted a record defeat for British Prime Minister Rishi Sunak's Conservatives at a July 4 election, forecasting the Labour Party would comfortably win a large majority after 14 years in opposition.

Polling by YouGov showed Keir Starmer's Labour was on track to win 425 parliamentary seats in Britain's 650-strong House of Commons, the most in its history. Savanta predicted 516 seats for Labour and More in Common gave it 406.

YouGov had the Conservatives on 108 and the Liberal Democrats on 67, while Savanta predicted the Conservatives would take 53 parliamentary seats and the Liberal Democrats 50. More in Common forecast 155 and 49 seats respectively.

Chris Hopkins, political research director at Savanta, said its projection put Labour on course "for a historic majority".

The three polls were so-called multilevel regression and post-stratification (MRP) surveys, an approach that uses voters' age, gender, education and other variables to predict results in every British voting district. Pollsters used the method to successfully predict the 2017 British election result.

They are largely in line with previous surveys predicting a Labour victory, but show the scale of the Conservatives' defeat could be even worse than previously thought.

YouGov's forecast of 108 seats for the Conservatives was around 32 lower than its previous poll two weeks earlier.

Both Savanta and YouGov predicted that the party of Winston Churchill and Margaret Thatcher could be left with the lowest number of seats in its near 200-year history contesting elections.

Sunak, who in a final throw of the dice last week pledged to cut £17 billion of taxes for working people if re-elected, has failed to turn the polls around so far in a campaign littered with missteps.

His task has been made harder by the surprise mid-campaign return to frontline politics by prominent Brexit campaigner Nigel Farage, a right-wing populist, whose Reform UK party threatens to split the right-of-centre vote.

Britain has a first-past-the-post electoral system, meaning Reform could pick up millions of votes across the country without winning any individual seats.

YouGov predicted Reform would win five seats and Savanta none. More in Common did not give a figure for Reform.

The Savanta poll, published by the Telegraph newspaper, said Sunak could even lose his own parliamentary seat in northern England, once considered a safe Conservative constituency, with the contest currently too close to call.

Sunak has acknowledged that people are frustrated with him and his party after more than a decade in power, dominated at times by political turmoil and scandal.

All three surveys projected several senior government ministers, including finance minister Jeremy Hunt, were on course to lose their seats.

Most opinion polls currently place Keir Starmer's Labour about 20 percentage points ahead of the governing Conservatives in the national vote share.

Other polls in recent days have also presented a grim picture for Sunak, with one pollster predicting "electoral extinction" for the Conservatives.

  - Reuters