Keir Starmer will be Britain's next prime minister with his Labour Party set to win a massive majority in a parliamentary election, an exit poll on Thursday indicated, forecasting Rishi Sunak's Conservatives would suffer historic losses.

Center-left Labour was on course to capture 410 of the 650 seats in parliament, an astonishing reversal of fortunes from five years ago when it suffered its worst performance since 1935.

The result would give Labour a majority of 170 and would bring the curtain down on 14 years of increasingly tumultuous Conservative-led government.