UK prime minister Rishi Sunak said he spoke to Boris Johnson “just the other day”, amid speculation about what role the former prime minister could play in the election campaign.

Mr Sunak said they had discussed “the risk” Labour leader Sir Keir Starmer poses to the UK, as he declined to say whether his Downing Street predecessor-but-one would hit the campaign trail for him.

There has been speculation that Mr Johnson, still seen by many Conservatives as a strong campaigner, might help drum up support for the Tories as they languish behind Labour in the polls ahead of the July 4th UK general election.

The UK prime minister told The Daily T podcast: “We’ve been in touch. We were in touch just the other day actually talking about the risk that Starmer would pose to our country’s security and the damage he would do.”

Asked whether Mr Johnson would campaign for him, Mr Sunak said: “That’s a question for him. He’s a busy guy as well.”

The relationship between the men has been tense since Mr Sunak’s resignation as chancellor under Mr Johnson’s premiership in July 2022, triggering a mass exodus of MPs from government and party roles.

Mr Sunak said he was “very proud of the things that we did together” before he became one of the first in a series of ministerial departures which ended in the former Tory leader’s downfall.

A rivalry between Mr Sunak and his former boss then emerged as he embarked on a campaign for Mr Johnson’s job, with both vying to take back control of the Tory Party after Liz Truss’ short-lived tenure as prime minister.

Mr Johnson entered the election fray on Friday, using his first Daily Mail column since the vote was called to attack Mr Starmer.

In a sign he will not remain silent in the campaign period, Mr Johnson claimed the Labour leader would be the “most dangerous and left-wing prime minister since the 1970s” and that the Opposition would not maintain its hefty poll lead as election day approached.