Veteran broadcaster Andrew Neil has issued proceedings for defamation against Jennifer Arcuri, the American businesswoman who claims to have had a four-year affair with Boris Johnson while he was London Mayor.

The claim, in which Ms Arcuri appears on the Court file as a litigant-in-person, arises from a dispute on Twitter in December 2021, which began over a disagreement regarding the effectiveness of COVID-19 vaccines.

It escalated to a point where Neil accused Arcuri of ‘clear libel and defamation’ following her tweeting of allegations about his inclusion in an address book belonging to deceased paedophile financier Jeffrey Epstein. Arcuri alleged that Neil was on the ‘pedo elite train’.

The former GB News presenter, now hosting a show for Channel 4, said Arcuri’s comments were ‘evil lies’ and ‘vile and untrue accusations’.

Neil has previously said that he never met the convicted child sex offender and that he was listed in the deceased businessman’s ‘black book’ because he had met Ghislaine Maxwell, who was last year found guilty of recruiting and grooming teenage girls for Epstein, in New York in the 1990s. In tweets about Epstein, Neil told another Twitter user he had no connection to him: ‘I’ve never even met him, communicated with him, never mind visited any of his properties or been on his planes, cars, buses, helicopters, ponies’ he said. ‘Now what is it you don’t understand about piss off. And apologise before you do, please, piss off.’

Neil wrote on Twitter that he had decided to take legal action ‘not just to hold Arcuri, who I’ve never met and have no interest in, to account but, more important, to establish that the twitterati can’t just promulgate evil lies without consequences. If you think anonymity will protect you, you’re in for a big surprise.’

In a tweet at the end of December, Neil told Arcuri: ‘My legal team has prepared a massive case against you and we’ll be seeking exemplary damages. Papers will be served in UK and US. I know you’ve been keeping your location private. But tell me, what’s it like in Panama City, Florida this time of year?’

Arcuri responded: ‘This guy is going to give himself a heart attack.’

Arcuri has taken down some of the tweets, although that is unlikely to do any more than mitigate damages at this stage.

The principal difficulty Neil is facing is that Arcuri is based in the US, where it is potentially difficult to enforce any English defamation judgment.