Labour MP Dan Jarvis has hinted he could join the growing list of contenders to succeed Jeremy Corbyn as party leader, following Labour's worst election defeat since the 1930s.
Mr Jarvis, who was elected Mayor of the Sheffield City Region in 2018, said he cared deeply about the party and wanted to "play my part" in its future.
A former major in the Paras nicknamed SEMOD (short for Steely-Eyed Messenger Of Death), Dan Jarvis was elected Labour MP for Barnsley Central in a 2011 by-rnelection.
He delivered a scathing verdict on Mr Corbyn's leadership, saying voters in the party's traditional heartlands like South Yorkshire felt Labour no longer spoke for them.
"Too many people said they weren't prepared to vote Labour this time. We have got to listen to those people," he told BBC Radio 4's The World at One.
"Yes, it is about the leader. It is about having someone who you can credibly present to the country as a prime minister.
"You have to be credible when it comes to the economy and when it comes to national security.
"You have to have a manifesto programme that is credible and speaks of the challenges the country faces now and in the future.
"Those are the things that we didn't do in the most recent general election ."
Pollsters YouGov found some 35% stopped voting for the party because of the leadership dwarfing the 19% concerned by the party’s Brexit policy after Labour suffered its worst result since the 1930s.
A further 16% were put off by the party’s policy and its economic incompetence.
The 47-year-old who has two children from his marriage to first wife Caroline, who died from cancer in 2011, and one with his second wife Rachel, who he married in 2013, has indicated he would reflect over the Christmas break on whether to run for the leadership himself.
Asked whether he could stand, he said: "I will be slightly suspicious of anybody who is declaring their candidacy on Christmas Eve.
"I have a very, very significant commitment as mayor. I take that very seriously, but I do want to play my part. I care deeply about the Labour Party, care deeply about the country."
Meanwhile another potential leadership contender, Lisa Nandy, has warned the party is in danger of learning the wrong lessons from the election.
She expressed concern about a controversial review, including former leader Ed Miliband, into its performance set up by the Labour Together group.
The Wigan MP said that although she was part of Labour Together she had only learned of the review two days ago.
She said people in the party should be getting out to speak to voters in constituencies like the former mining town of Ashfield in Nottinghamshire, which she visited after it fell to the Tories.
"There was just a general sense that at the top of the Labour Party, that we don't speak for people like them any more, a sense we don't have skin in the game, that we're not rooted in those communities, and we're just not like them," she told the Radio 4 Today programme.
"We need to be out in places like Ashfield, listening to people like the ex-miner I met yesterday, not sitting in meeting rooms in Westminster trying to debate this out amongst ourselves with the help of a few think-tanks.
"I just think the approach is wrong."
However, London mayor Sadiq Khan said it was right that Mr Miliband had a role to play in the election inquest.
"I want the next leader to unite our party, unite our country, unite those who voted Leave with those who voted Remain, unite the North with the South, the old with the young," he told PA.
"And that's one of the reasons why it's important not just Ed Miliband but many others look at why we lost and learn the right lessons."
Shadow Chancellor John McDonnell has also welcomed the post mortem.
He said: “I welcome this initiative by Ed Miliband. Elections are won and lost by a combination of long term trends and short term contingencies but we must also ensure that Labour remains as a party whose fundamental role is to change the world not just react to it.”
So far only Emily Thornberry and Clive Lewis have officially declared but Keir Starmer, Rebecca Long Bailey and Jess Phillips are widely expected to stand.
