Northern Ireland’s First Minister Arlene Foster has won £125,000 in damages after a television doctor tweeted an allegation of her having an affair.

The award is thought to be a UK record for defamation on the social network site.

Presenter Dr Christian Jessen has also been ordered to pay legal costs – pushing his bill up hundreds of thousands of pounds.

The judge called his Twitter comment “a most serious libel” and “grossly defamatory”.

Mr Justice McAlinden said he entirely accepted Mrs Foster’s statement that the “public trashing of the most precious relationship in her life by a prominent public figure gave her grave upset, distress, embarrassment and humiliation”.

The court heard ill-founded and baseless rumours had been circulating that Mrs Foster was “close” to one of her protection team.

Dr Christian Jessen

Dr Jessen – who presents -Embarrassing Bodies – tweeted the false affair allegation to his 300,000 followers

He described Mrs Foster as “the sanctity of marriage preaching woman”.

When he was legally advised to remove the comment, he replied “LOL” – and kept it up for a further two weeks.

Mrs Foster – married to her husband Brian for 25 years – told the court how she had to discuss the issue with her children two days before Christmas.

She said she believed the tweet was timed to undermine critical negotiations to restore a devolved Northern Ireland government.

Dr Jessen said he wasn’t aware the legal claim had reached a critical stage because he was unwell.

However, the judge said there was “no medical evidence of any nature to substantiate that”.

Also, claims the doctor had not received legal documents were “wholly unsatisfactory and unconvincing”.

Mr Justice McAlinden added:

“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 statement extolling the sanctity of marriage… as an adulterer, a hypocrite and a homophobe is a most serious libel”.

After the hearing Mrs Foster’s lawyer, Paul Tweed, said:

“Dr Jessen has been offered every opportunity to do the right thing from the outset but he has failed to do so.

“My client is grateful to the court for this total vindication which hopefully will act as a watershed for all women in public life who have been subjected to similar attacks on social media.”