Labour must pick its next leader from the emerging generation of MPs, a former cabinet minister has said as the party began a post-mortem examination of a disastrous General Election night that ended with Ed Miliband quitting after five years in charge.

Lord Hutton suggested long-term shadow cabinet favourites for the job such as Andy Burnham and Yvette Cooper should stand aside to allow younger challengers to fight for the right to try to make the Opposition an electoral threat to the Tories.

The leading Blairite said the "bitter" defeat at the polls had set the party back 30 years, blaming the lack of public appetite for an "old school socialist menu".

Mr Miliband said he took "absolute and total responsibility" for Labour being all but wiped out by the SNP in Scotland and failing to advance in the rest of the UK, handing David Cameron an overall Conservative majority.

The National Executive Committee (NEC) will meet early next week to set a timetable for a contest to replace both him and deputy leader Harriet Harman who will quit that post after steering the party through the interim.

Some in the party have urged a swift process to deny the Tories a chance to define the agenda, but others - including shadow education secretary Tristram Hunt, a potential candidate - have urged a longer period of reflection.

Among those tipped to throw their hats in the ring also include Chuka Umunna, Liz Kendall and ex-soldier Dan Jarvis - all of whom have been in the Commons for five years or less.

Lord Hutton, who held a number of senior roles including defence and business secretary under Tony Blair, said Labour could only win again " by taking a very careful look at ourselves and asking ourselves some very important questions about our nature and our characteristics as a political party".

"Labour has got to reflect very carefully on the lessons that we should draw from this election defeat. It is a very bitter one for us and we are now almost back to where we were 30 years ago in terms of number of MPs and our popular support," he told BBC2's Newsnight.

"I think a few of us, after the success we had in the 90s and 2000s, thought we would ever be in this position again. But we are in this position again. We have got to pick ourselves up, to ask ourselves some very difficult questions, about the kind of party we want to be."

Asked who he thought was capable of leading that process, he said: " I think it's probably time for a new generation of Labour politicians to step forward now. And I think there will be many who will and I hope we have a vibrant and interesting election campaign.

"Both Andy and Yvette are outstanding politicians who have contributed so much to a party and to our government and to our country. My own personal view is that we probably do need a generational change, a new generation of younger politicians who can grapple with the enormous challenges that they face

Asked if he meant figures such as Mr Umunna, Ms Kendall and Mr Jarvis, he said: "These are all very credible, very interesting politicians who have got something to say. Let's see what they have got to say, but until they do I'm going to keep my counsel."

Backbencher John Mann said Mr Jarvis was the "obvious" candidate.

" We need somebody who is not a political insider who has always been locked in Westminster," he told the BBC - and pledged to consult his constituents in a "primary" contest.

Tom Watson, the party's former deputy chairman, declared he would consider standing for deputy leader to replace Ms Harman.

Lord Hutton ruled out a return for David Miliband - who was the Blairite favourite to succeed Gordon Brown in 2010, b ut quit the Commons for a role in New York after being pipped to the leadership by his younger brother.

In a message on Twitter, David Miliband said: "Heart goes out to great colleagues who lost seats, Labour teams who worked so hard and of course to Ed.

"Deep and honest thinking required to rebuild progressive politics."