The High Court has ruled that a tweet by Sally Bercow about Lord McAlpine was libellous.
A subsequent hearing will determine the damages she owes him.
The wife of Buckingham and Winslow MP and Speaker, John Bercow published a tweet two days after a BBC Newsnight programme had wrongly implicated a ‘leading Conservative politician’ in sex abuse.
In a statement, Mrs Bercow said she was ‘surprised and disappointed’ by the High Court ruling.
She added: “However, I will accept the ruling as the end of the matter. I remain sorry for the distress I have caused Lord McAlpine and I repeat my apologies.”