TV presenter Dr Christian Jessen has been ordered to pay damages of £125,000 to Arlene Foster for posting an “outrageous” defamatory tweet which made unfounded claims that the First Minister of Northern Ireland was having an extramarital affair.

Delivering judgment in the case at the High Court in Belfast, Mr Justice McAlinden accepted that the false tweet by the celebrity doctor had cut Mrs Foster “to the core”.

Mrs Foster sued the celebrity medic, best known for appearing in the Channel 4 show Embarrassing Bodies, for defamation for the tweet he posted on December 23 2019, making the false allegation of an affair to his 300,000-plus followers.

The tweet remained online until Dr Jessen deleted it on January 7 2020.

Delivering judgment, Mr Justice McAlinden said: “To state that a woman married for 25-and-a-half years and a mother of three children, who is a committed Christian and who is recognised as such, and who has publicly made statements extolling the importance and sanctity of marriage, who also happens to be the leader of the Democratic Unionist Party and a holder of the office of First Minister of Northern Ireland, was an adulterer, a hypocrite and a homophobe is a most serious libel and is grossly defamatory.

“It is an outrageous libel concerning an individual of considerable standing, attacking her integrity at the most fundamental level, and it involves the trashing in a very public fashion of the relationship that Mrs Foster holds dearest in her life.

“It affected core aspects of her life, namely her relationship with her husband, her deep Christian faith, it called into question her fitness and suitability to occupy the office of First Minister at a time when delicate negotiations were continuing on the re-establishment of the Northern Ireland Executive.

“In short, I consider that it was an outrageously bad libel.”

Mr Justice McAlinden continued: “The offending tweet remained on the defendant’s Twitter account for two weeks, a Twitter account with 311,000 followers.

“The tweet was liked approximately 3,500 times and it was retweeted 517 times. The fact that the defendant failed to take down the offending tweet was the subject of mainstream media coverage.

“This outrageously bad libel cut her (Mrs Foster) to the core, causing her considerable upset, distress, humiliation, embarrassment and hurt.

“Bearing in mind the time of year and the work-related pressures the plaintiff was under at that time, I fully accept this libel took a heavy emotional toll despite her experience of dealing with the heat of robust political debate.

“Her marriage, her family life and her faith are the most important things in her life. These things provide important pillars of support and it was these things that were publicly trashed.”

Mr Justice McAlinden ordered Dr Jessen to pay damages of £125,000 and Mrs Foster’s legal costs.

Giving evidence last month, Mrs Foster told the court the incident came at a particularly stressful time when she was involved in talks to resurrect the powersharing government in the region.

She said she felt the rumour of the affair with a close protection officer, which she described as having emerged online from anonymous accounts before the tweet by Dr Jessen, was designed to destabilise her at a critical time.

“I think the attack on me personally and my marriage was meant to destabilise me at a very critical time,” she told the court.

“It was meant to destabilise me and thereby destabilise the negotiations as well.

“I have no proof of that, but I just think the timing of it is very significant given when it came.”

A key issue in the case was the TV doctor’s repeated failure to engage in the legal process and respond to papers served on him by Mrs Foster’s representatives.

Dr Jessen first engaged with the legal proceedings after Mrs Foster had already given evidence to the court.

He claimed he had been previously unaware the case at Belfast High Court was happening.

Dr Jessen previously told the court that he had moved out of his London city centre flat at the time and into his parents’ home as he was suffering from mental health issues and had not been watching the news.