Arlene Foster was left humiliated after a celebrity doctor "trashed" her marriage with false social media allegations over an affair with a close protection officer, she told the High Court yesterday (Wednesday).

The First Minister and Democratic Unionist Party leader said television presenter Christian Jessen's categorically untrue tweet about the state of her relationship with her husband of 25 years inflicted deep hurt at a time when she was attempting to restore power-sharing in Northern Ireland.

The distress caused to Mrs Foster and her family was compounded by the posting being made two days before Christmas in 2019.

She said: "It was almost as if this cut to the very core of my life."

Judgment was reserved at a hearing to determine the level of damages to be awarded.

Defamation proceedings were brought against Dr. Jessen for the tweet on his account with more than 300,000 followers.

The Harley Street medic, best known for presenting Channel 4 shows Embarrassing Bodies and Supersize v Superskinny, has not entered a defence to the libel action.

Counsel for Mrs. Foster set out how the tweet posted on December 23 was only removed two weeks later.

During that period it received 3,500 likes and was retweeted more than 500 times as "the mob joined in", according to David Ringland QC.

He argued that the libel was further aggravated by Dr. Jessen further tweeting "LOL (Laugh Out Loud)" on Christmas Day after being put on notice by Mrs. Foster's solicitor.

A day later the defendant allegedly posted: "People are now comparing me to Barbra Streisand - this gay boy's life cannot get any better!!!!."

Mr Ringland contended: "That's a sneering tweet, with sneering content, and it's presentation is also a high-level sneer at the way my client is approaching this either personally or through her solicitor."

The court heard Mrs Foster was left with no alternative but to take legal action over the false and highly defamatory posting.

Correspondence sent to Dr. Jessen stated: "Furthermore, your facetious reference to the actor Barbra Streisand intended to smugly highlight, albeit misconceived, references to an alleged Streisand effect of our client's public statement, together with your positive acknowledgement and encouragement of retweets has further exacerbated the damage caused to our client's reputation by portraying her as a liar and hypocrite in her said denials.

"For the record, our client would again categorically and emphatically deny that she has had an affair with her driver and that her marriage is a sham."

At the time Mrs Foster was heavily involved in talks aimed at getting the devolved institutions at Stormont back up and running.

Giving evidence, she told Mr Justice McFarland other anonymous accounts made similar baseless attacks on her marriage in what she believed was an attempt to destabilise those negotiations.

She recalled the deep upset felt at having to speak to her husband after being alerted to the tweet on Dr. Jessen's account.

"This gentleman (the defendant) has a large following, so this was going to go far and wide," Mrs. Foster said.

"It was very humiliating to see the relationship that's most important to me had been trashed, if you like, and put out there in the public domain in that fashion."

At the time she received support from political colleagues, opponents and the Secretary of State, the court heard.

But some DUP councillors in her native County Fermanagh were contacted by constituents asking if there was any truth in the allegations.

"They didn't come to me to find out if it was true, and that was quite distressing," she added.

Asked what caused the most hurt, Mrs. Foster replied: "The allegation that I was having an adulterous relationship with one of my police officers clearly was the most hurtful issue.

"I have been married to my husband now for 25 and a half years, before we got married we were going out in inverted commas for nine years. It's a long relationship.

"As a woman in politics and as a leader we come under a lot of stress and strain, but one of the things that gives me stability in my life is my home relationships."