David Cameron, 57, served as British prime minister from 2010 to 2016, resigning after the outcome of the Brexit referendum, when Britain voted to leave the European Union.

His unexpected return to the front line of British politics comes after he spent the last seven years writing his memoirs and involving himself in business, including Greensill Capital, a finance firm which later collapsed.

Greensill’s demise fuelled questions about the extent to which former leaders can use their status to influence government policy after Cameron repeatedly contacted senior ministers in 2020 to lobby for the firm.

Sunak’s office said on Monday that King Charles had approved giving Cameron a seat in Britain’s upper chamber, the House of Lords, allowing him to return to government as a minister despite no longer being an elected member of parliament.

Under fire from opposition MPs and members of the governing Conservative Party to eject interior minister Suella Braverman, Sunak seemed to have brought forward a long-planned reshuffle.

Sunak was forced to sack the interior minister when the ever-controversial Braverman defied him last week in an unauthorised article accusing police of “double standards” at protests, suggesting they were tough on right-wing demonstrators, but easy on pro-Palestinian marchers.

The opposition Labour Party said that inflamed tensions between a pro-Palestinian demonstration and a far-right counter protest on Saturday, when nearly 150 people were arrested.

Cameron said he was glad to take on his new role because at a time of global change, “it has rarely been more important for this country to stand by our allies, strengthen our partnerships and make sure our voice is heard”.

“Though I may have disagreed with some individual decisions, it is clear to me that Rishi Sunak is a strong and capable prime minister, who is showing exemplary leadership at a difficult time,” he wrote on X, formerly Twitter.

MPs in the centrist wing of the party said Cameron’s appointment would bring international experience, and send a wider message to the country.

“It’s a sign to the Tory blue wall and moderate voters, we aren’t heading to the right,” one Conservative MP said, using a phrase that is used to describe traditional Conservative-supporting areas in the south of England.

Some Brexit supporters also said the fact Cameron had campaigned for Britain to stay in the European Union after he called a referendum on membership for 2016 meant the so-called “remain” wing of the party had taken over.

Braverman was replaced by James Cleverly, who had relished his job as foreign minister but who is seen as a safe pair of hands.

With Braverman sidelined, her attentions might focus on preparing for a possible future race for leader of the party if, as the opinion polls suggest, the Conservatives lose the election expected next year.

The Labour Party has consistently held an around 20-point lead in the polls, and Sunak has failed to reduce that gap.

MP Pat McFadden, Labour’s national campaign co-ordinator, said: “A few weeks ago Rishi Sunak said David Cameron was part of a failed status quo, now he’s bringing him back as his life raft.”

“This puts to bed the prime minister’s laughable claim to offer change from 13 years of Tory failure.”