A celebrity doctor has said he posted false rumours that Northern Ireland’s First Minister was having an affair to expose any possible hypocrisy.

Dr Christian Jessen told the High Court in Belfast that he didn’t want to cause Arlene Foster “any distress” when he tweeted an unsubstantiated rumour of an extra-marital affair.

He admitted that the tweet, posted in December 2019, would have been “unpleasant” for her.

The TV presenter, who appeared in court for the libel proceedings, said he posted the tweet based on rumours he read about on social media.

The rumour was based on an allegation she had an affair with a close protection officer.

Dr Jessen, who is best known for the Embarrassing Bodies TV show on Channel 4, is being sued over the tweet.

“There was extensive online comments about this rumour,” Dr Jessen told the court.

“It wasn’t just one or two, there were many hundreds of tweets going back quite some time about this rumour.

“It seems too prolifically talked about to have been conjured from thin air.

“The comments and articles that were around at the time. It was covered in a number of disconnected websites.”

Dr Jessen was questioned about the basis of his tweet by David Ringland QC, acting for Mrs Foster.

Mr Ringland asked the celebrity doctor why he tweeted the “disgusting” falsehood about the first minister.

The defence barrister accused him of “trashing” Mrs Foster’s reputation.

Dr Jessen told the court he wanted to highlight “possible hypocrisy behind it”, referring to the Democratic Unionist Party’s position on same-sex marriage and abortion.

“What I had presented to me, from the myriad of corners from which I was seeing this same rumour repeated, that I could conclude that (it) was not false,” he added.

“My issue was more the possible hypocrisy behind it.

“Given the extent of the rumours and given the DUP’s stance on things like equal marriage and abortion, I felt strongly that if there was a possibility that these were true, this is a public figure that was answerable to her public.

“If there were any truth to these, that hypocrisy needs to be pointed out and accounted for.

“I was interested in making sure that if there was any truth in it, that any hypocrisy that may have been behind it was noted.”

Mr Ringland put it to Dr Jessen that he posted the allegation to his 300,000 followers based on rumours that were “possibly true”.

“Do you understand how shattering and damaging it is for a happily married woman to be accused of adultery?” Mr Ringland added.

Dr Jessen replied: “I’m sure it was very unpleasant for her and I would not wish to cause her any distress.”

Mrs Foster previously told the court how she felt “humiliated” by the tweet, which came at a particularly stressful time when she was involved in talks to resurrect the powersharing government in the region.

A ruling on the scale of damages was delayed after Dr Jessen was cross-examined on claims he was not aware that legal proceedings had commenced.

He told the court he had not watched or read news in the last 12 months and believed that all court proceedings were suspended because of the pandemic.

Dr Jessen, who is soon to be working as a Covid-19 vaccinator for the NHS, also told the court that he moved back to his parents’ home in March last year because of his mental health problems.

Counsel for the DUP leader cross-examined Dr Jessen for more than three hours over claims he did not receive correspondence from Mrs Foster’s legal team.

Dr Jessen said he gave up his job in January 2020 because he was too ill to carry on with his work.

The court heard how he was going through a “distressing time”.

“I had to make some major life decisions at that time and I had stopped my work in the hope I would be able to get back on track with my health,” he added.

“I tried my best to do that, it didn’t work. In fact things got worse for me and around this time I took the decision that I needed to move home with my parents.

“I wasn’t coping with life very well and I needed some help from family.

“This was a really dark and confusing time for me.”

Over lengthy exchanges over claims he did not receive correspondence about legal proceedings, Mr Justice McAlinden asked Dr Jessen if he “buried his head in the sand” because of his mental health issues.

Dr Jessen replied: “I don’t think so. No, not at that time. I really don’t.”

The judge added that people with mental health problems sometimes do things that “don’t make sense”.

Dr Jessen also told the court it was “very hard” for him to explain why he had not received any documents or letters relating to libel proceedings.

The defence counsel accused him of being “entirely dishonest” about the claims.

“I put to you, that your answers to most of the questions on (postal) service appear to bear no relationship to reality that anyone in the court has encountered,” Mr Ringland added.

Mr Ringland also accused Dr Jessen of trying to cover up a delay in removing the tweet until he got advice from his solicitors in London.

“Your evidence has been prevalent with lies,” Mr Ringland added.

“You have been called out overtly on a number of occasions, not least in relation to the lie you told on January 7 with a view to disguise, at that stage, the delay in taking down the tweet.”

The case has been adjourned until Tuesday next week.