Ed Miliband quit after an astonishing election with Labour virtually wiped out in Scotland and David Cameron’s Tories securing a Commons majority.
The Opposition leader said he took “absolute and total responsibility” for the result, offering apologies to Labour veterans – including ex-Nottingham High School alumnus Ed Balls and Jim Murphy – who lost their seats overnight.
He told supporters: “Britain needs a strong Labour Party, Britain needs a Labour Party that can rebuild after this debate so we can have a government that stands up for working people again.
“And now it is time for someone else to take forward the leadership of this party. So I am tendering my resignation, taking effect after this afternoon’s commemoration of VE Day at the Cenotaph.
“I want to do so straight away because the party needs to have an open and honest debate about the right way forward, without constraint.”
A clutch of candidates are thought likely to stand for the Labour leadership – including heavyweights Andy Burnham and Yvette Cooper as well as newer faces like Chuka Umunna.
Rather than breaking through as forecast by opinion polls, Labour saw losses to the Tories in key marginal seats and failed to win the Conservatives’ most vulnerable constituencies.
Labour was decimated north of the border as Nicola Sturgeon’s Scottish National Party, which won just six seats five years ago, secured 56 seats this time round.
UKIP leader Nigel Farage also stood down after his party failed to capitalise on its pre-election ambitions.
Despite coming third behind the Conservatives and Labour in terms of share of the vote, the Eurosceptic party won just one seat in the Commons, Mr Farage himself failing to win South Thanet.
But no party would have been reeling more than the Liberal Democrats, who suffered humiliation after losing an incredible 48 seats overnight.
Nick Clegg’s party, which formed part of the Coalition in the previous government, saw a spate of high-profile casualties like Vince Cable, Danny Alexander, Charles Kennedy Ed Davey.
As a result, Clegg went on to resign as leader of the Lib Dems, the third major political leader to fall on his sword post-election.