Lawyers on behalf of a pro-union campaigner claim to have begun legal action against Glasgow East MP Natalie McGarry.
Alastair Cameron, who runs grassroots unionist group Scotland in Union, released a statement on Friday saying that he has begun legal action against McGarry over comments allegedly made on Twitter. He has instructed his lawyers to serve a writ against the Glasgow East MP.
However, McGarry's lawyer says that no writ has been served and no further comment would be made on the matter.
Cameron said: "Reluctantly, I have been forced to take this action because of Ms McGarry’s failure to respond to my request for an appropriate apology for her offensive and inaccurate comments on Twitter.
“It is not acceptable for a Member of Parliament, in a public position of power and responsibility, to make such an awful accusation against someone and then simply brush it off.
“I am still optimistic that we can resolve this quickly and amicably, and my solicitors await a response from her. We look forward to drawing a line under this regrettable incident and moving on from smears and unfounded accusations to a more decent and respectful political discourse in Scotland.”
Aamer Anwar, McGarry's lawyer, said: "Having spoken to Ms McGarry this morning, she has confirmed that no writ has been served on her.
"There will be no further comment."
STV News understands that the writ was sent on Thursday evening by solicitors acting on behalf of Cameron.
McGarry was elected as an SNP MP but has since resigned from the party whip after a dispute over funding of the pro-independence campaign group Women for Independence.