Rishi Sunak insisted he had a “very good chat” with Boris Johnson after the pair were not seen together at a Tory rally.

The former prime minister made a surprise appearance at the London event on Tuesday night in a bid to give the faltering Conservative campaign a late boost.

Greeted by applause and chants of “Boris, Boris, Boris”, Mr Johnson used his speech to issue warnings about a Labour government and Reform UK.

But he did not make a positive case for Mr Sunak and the duo were not pictured together.

Asked by journalists on the campaign trail on Wednesday whether he had met his predecessor, Mr Sunak said: “Of course. I had a very good chat with him.

“What you saw is all Conservatives … united in warning the country about the dangers of what Keir Starmer would mean, undoing all the progress that we’ve made.

“And as Boris rightly pointed out, just at the moment where we have gone through Covid, the impact of the war in Ukraine and we’re now cutting people’s taxes and can look forward to a better future, we would throw all that away if Keir Starmer was in power.”

The current and former occupant of Downing Street have a fraught relationship, with Mr Sunak’s resignation as chancellor in Mr Johnson’s cabinet instrumental in the latter’s downfall.

Mr Johnson had been largely absent from the campaign trail, although supportive of the Tories in his newspaper column, and had been writing letters of endorsement and backing a number of candidates in social media posts.

He took a holiday to Sardinia earlier in the run-up to the General Election, in which polls suggest the Conservatives could suffer a crushing defeat.

Taking to the stump on Tuesday, Mr Johnson told activists in Chelsea that Sir Keir Starmer would try to “usher in the most left-wing Labour government since the war”.

Making a reference to “other parties” allegedly “full of Kremlin crawlers”, Mr Johnson said: “Don’t let the Putinistas deliver the Corbynistas.

“Don’t let Putin’s pet parrots give this entire country psittacosis – which is a disease you get by the way from cosying up to pet parrots.”

Sir Keir said he was unfazed by Mr Johnson’s intervention.

“Last night they wheeled out the architect of chaos and division, so I think that just shows the kind of desperate, negative place they’ve got to with their campaign,” the Labour leader told broadcasters on a campaign visit to Carmarthenshire.

Liberal Democrat leader Sir Ed Davey said the Tories’ decision to bring Mr Johnson into their campaign was “a bit weird”.

“I think the Conservatives’ desperate tactics are a bit weird, reminding people of the failures – the failures of Boris Johnson, the failures of Liz Truss, of Rishi Sunak,” he told the PA news agency.

Reform UK leader Nigel Farage said Mr Johnson’s appearance was “absolutely irrelevant” to his party’s electoral prospects.

He told PA: “He’s a busted flush. He’s the reason they’re in so much trouble.