Sir Keir Starmer appointed the senior MP, who was a minister under Gordon Brown, as shadow minister for creative industries and digital on Wednesday.

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It means Sir Chris has to vacate his prominent position as chairman of the Commons Standards Committee, which scrutinises the behaviour of MPs.

Writing on X, formerly Twitter, he said he was "delighted" to accept the new role and would be resigning from the cross-party panel with immediate effect.

He quipped "and I mean immediate effect" - a parting dig at Nadine Dorries, the Tory MP he sought to oust from parliament after she delayed her formal resignation.

Sir Chris has chaired the standards committee since 2020 - a role that catapulted him into prominence amid a series of Westminster sleaze scandals.

It was this committee that recommended former Tory MP Owen Paterson be suspended from the House of Commons for 30 days for an "egregious" breach of lobbying rules.

It sparked a huge row as Conservative MPs, led by then prime minister Boris Johnson, sought to save him from punishment and overhaul the standards system.

The government was ultimately forced into a U-turn following accusations of sleaze, but the scandal marked the beginning of the end of Mr Johnson's tumultuous time in office.

Sir Chris, one of the most vociferous critics of Mr Johnson, acknowledged the "major controversies" the committee has overseen in a letter confirming his resignation.

He paid tribute to the work the panel has done to clean up standards but warned there is still "significant room for reform".

Commons rules mean the chairperson of the standards committee must come from the Opposition, so Sir Chris's successor will be a Labour MP elected in a secret ballot of MPs.

The MP for Rhondda's return to the frontbench is another example of Sir Keir bringing in those with experience from Labour's last time in government.

In Mr Brown's administration, Sir Chris served in the Foreign Office, including as Europe minister, having been deputy Commons leader.

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He also spent nine months as shadow Commons leader under Jeremy Corbyn, but quit as part of a wave of resignations from the shadow cabinet, saying he feared the then-leader would "go down in history as the man who broke the Labour Party".

Sir Keir began his reshuffle on Monday, promoting centrists at the expense of some MPs on the soft left.

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A spokesman for the leader said appointments to the junior ranks would continue on Wednesday.

He denied the Opposition leader was acting ideologically during his reshuffle.

Sir Keir's spokesman told reporters: "What Keir's priority has been throughout this reshuffle has been promoting people of competence and commitment into the roles that they have got, not questions of ideology.

"What we want to ensure is that we have got a team that is ready for the campaign and, if we are lucky enough to win the next general election, then we will be ready for government."