Former prime minister Rishi Sunak has urged the Conservative Party to cease its infighting, in his final address to Tory members before he stands down as leader.

Mr Sunak, who oversaw the Conservatives’ worst election loss in living memory during the summer, warned the party would face further defeats if it did not unite following the ongoing election to choose his successor.

Leadership candidates James Cleverly, Kemi Badenoch, Tom Tugendhat and Robert Jenrick were urged at the outset of the contest by party officials not to attack one another openly as they campaigned.

At a reception event in Birmingham, hundreds of Tory members gathered to hear Mr Sunak’s final address as leader of the party.

He cracked jokes about Sir Keir Starmer’s acceptance of freebies and gifts, claiming the conference was such a “hot ticket” he was surprised the Labour leader “hasn’t asked someone to buy it for him”.

The Richmond and Northallerton MP also apologised to Conservative members at the party conference for the summer election loss.

“I am only sorry that your efforts could not deliver the results you deserved,” he told the reception in Birmingham, his only significant appearance at the conference.

“It wasn’t you,” a member shouted back.

Mr Sunak then concluded his speech with a “final ask” of Tory members.

“Whoever wins this contest, give them your backing,” he said.

He added: “We must end the division, the backbiting, the squabbling. We must not nurse old grudges but build new friendships.

“We must always remember what unites us rather than obsess over where we might differ, because when we turn in on ourselves we lose and the country ends up with a Labour government.”

Rishi Sunak with his wife Akshata Murty
Conservative party leader Rishi Sunak with his wife Akshata Murty arriving in Birmingham on the eve of conference (Stefan Rousseau/PA)

Mr Sunak had earlier wrote an article in which he said the Conservatives should “learn the lessons” of their general election defeat and “reflect” on their time in government as their conference gets under way.

Mr Sunak described this year as a “difficult one” for the party as “too many good Conservatives have lost their seats”, in a piece for The House magazine.

He said he “will always be sorry” that “he could not deliver the results that everyone’s efforts deserved”, in the article at the start of his final conference as leader.

Writing in the magazine, Mr Sunak described the conference as an “important moment for our party”.

He added: “This is our first conference in opposition since 2009. Of course, we need to learn the lessons of our defeat: we did not get everything right in government – no government ever does – and we do now need to reflect on that. But we should not forget what we have achieved since 2010.”

Mr Sunak announced he would be standing down as the party leader following the election defeat in July.

The winner of the leadership contest is due to be announced at the start of November.