Tony Blair is warning that Labour will be "replaced" as a serious political force if it tries to "whitewash" the scale of its election defeat.

The ex-prime minister will unveil research suggesting Labour's problems go "far deeper" than the unpopularity of Jeremy Corbyn and its Brexit stance.

He will say in a speech that the party faces electoral oblivion unless it changes course.

Mr Corbyn has said he will stand down as leader "early next year".

• LIVE: Tony Blair speech on Labour's future
• Who will be Labour's next leader?

At a meeting of Labour MPs on Tuesday, he said he "took responsibility" for Labour's worst electoral performance, in terms of seats won, since 1935.

But he was criticised to his face by Labour colleagues, with former MP Mary Creagh saying the lack of a personal apology showed he was a "man without honour and without shame".

Shadow Brexit secretary Sir Keir Starmer told the Guardian he was "seriously considering" running to be Labour leader, saying it was time for the party to return to being a "broad church" and praising Momentum as well as "people who might self-identity as Blairites".

He said: "It is a devastating result, but it's important not to oversteer. The case for a bold and radical Labour government is as strong now as it was last Thursday. We need to anchor ourselves in that."

He is one of a number of senior Labour figures, including MP for Wigan Lisa Nandy, to say they are weighing up running to succeed Mr Corbyn - but none have officially confirmed they are standing yet.

Former Work and Pensions secretary Yvette Cooper said she would "decide over Christmas" on whether she would run.

Speaking to Radio 4's Today programme, she said Labour had "a long road to travel", adding that the party needed to tackle anti-Semitism, restore "kindness to our politics" and be more "inclusive".

Labour ended up with 59 fewer MPs than two years ago. While its share of the vote, at 32.2%, was higher than in either its 2010 or 2015 defeats, it was a far cry from the 41.9% it secured under Mr Corbyn in 2017.

And the collapse of its so-called "red wall" of seats in the Midlands, the North East of England and the North of Wales - some of which turned blue for the first time in 100 years - marked a watershed moment for the party.

Speaking on the BBC's Newsnight, Labour peer Lord Falconer described a "volcano of molten anger" in the party.

"The sense of hostility towards the leadership of the party, the way the election was conducted, the extent to which it was a massive failure to have the election at all, the extent to which colleagues who've lost seats have been abandoned, it is absolutely tangible in the air, it is so powerful, the anger," he said.

Rachel Reeves, Labour MP for Leeds West, told the programme that the party's leadership should "say sorry" to MPs who lost their seats and to people "who desperately need a Labour government".

'Main explanation'

Among the Labour seats to fall to the Conservatives was Mr Blair's former constituency Sedgefield, which he represented for 24 years, and which has not had a Tory MP since the 1930s.

• Thornberry 'warned Labour over Brexit neutrality'
• Why Blyth Valley changed its mind
• Can Tories deepen shallow roots?

Mr Blair, who won three general elections in a row between 1997 and 2005, will use a speech in London to warn of an existential threat to Labour.

He will say that while many Labour voters abandoned the party because of concerns over its Brexit policy - one of the reasons cited by Mr Corbyn and others at the top of the party - the issue was not the "main explanation" for the party's retreat in so many traditional heartlands.

He will point to research carried out by Deltapoll, for the Tony Blair Institute, which spoke to Labour voters in three marginal seats - Bishop Auckland, Walsall and Bassetlaw - in the final week before the election.

'Unthinkable losses'

The research, entitled Northern Discomfort, identifies Mr Corbyn's leadership and the "politics he represents" as the main cause of the "rupture with long-held loyalties" and the alienation felt by many traditional Labour voters.

Other factors it cites for the "unthinkable losses" suffered by Labour were concerns over a lack of economic credibility in its public spending and renationalisation proposals, the leadership's stance on security issues and a feeling the party had not done enough to root out "extremism".

BBC