Jeremy Corbyn has appeared to snub a formal inquest into Labour’s disastrous performance in the general election.

The Labour leader is not taking part in the probe into what went wrong at the polls, The Independent understands, which is due to examine the root causes behind the party’s worst electoral defeat since before the Second World War.

Headed up by former leader Ed Miliband, the inquiry is expected to report that Labour was hopelessly outmatched by the Tories in its digital campaign, while activists on the ground were repeatedly confronted with concern about Mr Corbyn, insiders said.

The damning report is expected to be released on the eve of the announcement of the next Labour leader, with a source saying: “We want it to be the first thing in the new leader’s in-tray.”

The news comes ahead of the final stage of the race to succeed Mr Corbyn, with candidates facing a Valentine’s Day deadline to win sufficient support from affiliated trade unions and local parties.

Shadow cabinet members Sir Keir Starmer and Rebecca Long-Bailey, and Wigan MP Lisa Nandy have already passed the threshold to get onto the ballot paper but Emily Thornberry, the shadow foreign secretary, is struggling to make up ground.

While the leadership contest is dominating the headlines, a group called Labour Together, made up of people different wings of the party, is trawling through views from members, ousted MPs and Labour supporters on what went wrong in 2019.

Insiders said it was clear that the Tories had significantly upped their online game since the 2017 election, which meant the party benefited from people sharing its message organically, rather than through paid advertisements.

Mr Corbyn’s leadership also repeatedly featured on the doorstep, with newspaper reports on his associations with Sinn Fein during IRA bombing campaigns appearing to resonate more strongly than in the previous election.

Insiders said the report will show that voters wanted “a hand up, not a hand out” and pointed to strategic mistakes by the party leadership.

“There is a lot of anger from the left over why we did not adopt a more defensive strategy,” the source added.

The report is also expected to find it will be impossible for Labour to win a majority in 2024 without making up lost ground in Scotland – or winning deeply entrenched Tory heartland seats. “Jacob Rees-Mogg’s seat [North East Somerset] is the one that we would need to win to get a majority without Scotland,” a source said.

Sources close to Mr Corbyn said he would take part if he had been asked but no approach had been made.

More than 8,000 people have submitted evidence to the review ahead of the 21 February deadline, with gimmicky policies, factionalism and inefficiencies among the complaints raised.

The battle to replace Jeremy Corbyn as Labour leader Show all 8 1 /8 The battle to replace Jeremy Corbyn as Labour leader The battle to replace Jeremy Corbyn as Labour leader Keir Starmer The former director of public prosecutions undoubtedly has announced that he is standing for the leadership. He is highly-regarded by both left-wingers and centrists in the party. As Labour’s shadow Brexit secretary, he played a key role in the party’s eventual backing of a second referendum. Before becoming an MP, he was a human rights lawyer - conducting cases in international courts including the European Court of Human Rights. Launching his bid, Starmer said that Labour must listen to the public on how to change "restore trust in our party as a force for good." A YouGov poll places him comfortably in the lead as the preferred candidate of 36% of party members EPA The battle to replace Jeremy Corbyn as Labour leader Lisa Nandy Wigan MP Lisa Nandy has announced she wil stand for the leadership. In a letter to the Wigan Post she said she wanted to bring Labour "home" to voters in its traditional strongholds who have abandoned the party. Nandy went on to say that she understands "that we have one chance to win back the trust of people in Wigan, Workington and Wrexham." A YouGov poll shows that Nandy is the first preference for 6% of partymembers. Getty The battle to replace Jeremy Corbyn as Labour leader Rebecca Long Bailey A key ally of the current left-wing leadership of the party, the Salford & Eccles MP is viewed in some quarters as the natural successor to Mr Corbyn and describes herself as a “proud socialist”. Highly regarded by the shadow chancellor, John McDonnell. She won also won plaudits for her performance filling in for Corbyn both at prime minister’s questions and during the general election debates. The shadow business secretary grew up by Old Trafford football ground and began her working life serving at the counter of a pawn shop. Launching her leadership bid, Long Bailey said the party needs to make the positive case for immigration as a "positive force." She also broke with Corbyn over Trident, saying "If you have a deterrent you have to be prepared to use it." PA The battle to replace Jeremy Corbyn as Labour leader Angela Rayner - Deputy leadership Shadow education secretary Angela Rayner has joined the contest for deputy leadership of the party. After ruling herself out of running for the leadership, the Ashton-under-Lynne MP launched her bid for deputy warning that Labour faces the "biggest challenge" in its history and must "win or die." She is close with leadership contender Rebecca Long Bailey PA The battle to replace Jeremy Corbyn as Labour leader Rosena Allin-Khan - Deputy leadership Shadow sport minister Rosena Allin-Khan said Labour need to listen with "humility" to lost voters as she launched her bid for the deputy leadership. Writing in The Independent, the MP for Tooting refelcted: "We shouldn’t have ignored the warning signs in Scotland, and now we’ve paid the price in northern England, across the midlands and in Wales." PA The battle to replace Jeremy Corbyn as Labour leader Dawn Butler - Deputy leadership Shadow women and equalities secretary Dawn Butler was first to announce her bid for the deputy leadership. The Brent Central MP has served in Jeremy Corbyn's shadow cabinet since 2016 PA The battle to replace Jeremy Corbyn as Labour leader Ian Murray - Deputy leadership Labour's only MP in Scotland said that the architects of the party's "catastrophic failure" in the December election can not be allowed to lead the party forward PA The battle to replace Jeremy Corbyn as Labour leader Richard Burgon - Deputy leadership Shadow justice secretary Richard Burgon is standing as a continuity candidate, flaunting his loyalty to Jeremy Corbyn and saying it is wrong to blame the current leader for the election defeat PA

An early release from the review, first published in The Guardian, found the free broadband policy was seen as “gimmicky and distracting” while digital tools were “clunky”.

But the inquiry has also attracted controversy within Labour over its decision to appoint Mr Miliband to lead, after he led the party to a poor showing in 2015.

It comes after a separate internal report, presented to Labour’s ruling body, absolved Mr Corbyn of responsibility and instead blamed Brexit and “unrelenting” media attacks on his character for the defeat.