LABOUR called on Alex Salmond to apologise for "dirty tricks" as it denounced allegations that threats had been made by one of its members against a female SNP MP.

It came as Liberal Democrat and Conservative MPs lined up to contradict the SNP’s claims a senior Labour MP had made a threatening comment that the woman would “get a doing”.

However, the SNP stood by their claims last night and said they had been “implicitly acknowledged” by the Labour MP involved, deputy leadership candidate Ian Davidson.

He insisted yesterday he had not made any such threat to Dr Eilidh Whiteford.

“I did not threaten anyone and did not intend to threaten anyone,” he said: “I apologise if anyone took offence but reiterate no threat was made or intended.”

The row broke out on Tuesday night after Ms Whiteford, the SNP MP for Banff and Buchan, withdrew from a Commons committee saying Mr Davidson, its chair, had said she would “get a doing” if details of a private discussion were leaked to the media.

The SNP also said no member of its party would sit on the Scottish Affairs Committee again until Mr Davidson resigned.

Senior Labour sources said a comment had been made during a private meeting of the committee last week.

However, they disputed the SNP version of events and said the comment had been made in the past tense, to reflect criticism Ms Whiteford had received from other members of the committee, and had been entirely in a political context. During a meeting of the committee yesterday members lined up to disagree with the SNP’s claims.

Alan Reid, a LibDem, said he was “very surprised” at the allegations, and the length of time they took to emerge. “I was present for all of the private meeting last week and I’ve no recollection whatsoever of any threats being made to anybody and I’m sure if a threat had been made I would have remembered it,” he said.

Two Conservative MPs also disagreed with the SNP. Mike Freer, the MP for Finchley in London, said: “I was also (there) and there was a robust discussion about the inquiry and the honourable lady was somewhat sensitive to the criticism but I didn’t hear those comments that were supposed to have been made at all.”

Labour last night demanded an investigation into the SNP’s operations, including that of the party’s Westminster leader and campaign director Angus Robertson, who accompanied Ms Whiteford yesterday when she informed the Commons speaker of her decision to withdraw.

A Labour spokesman said no threat had been made and “to suggest otherwise is simply a deliberate attempt to smear the chair of the committee which brings politics into disrepute”.

“It is never right to threaten a person – and it is never right to smear one either,” he added.

“The SNP must now conduct an inquiry into Angus Robertson and the SNP’s Westminster press office over the very serious questions about their conduct, their behaviour and disgraceful way in which this dirty tricks campaign appears to be orchestrated at the highest levels of the SNP.”

The First Minister should also apologise for his comments calling on Mr Davidson to resign, he said.

However, Ms Whiteford hit back, saying Mr Davidson was implicitly acknowledging he had made inappropriate remarks.

He “clearly still does not recognise why his comments during and after last week’s meeting were inherently threatening and unacceptable,” she said.

In a separate development 13 campaigners, including two professors, wrote to The Herald over the allegations.

“This incident is the latest evidence of the dominance of a sexist and antiquated political culture that underlies our political and economic institutions,” the academics and equality campaigners warned.

“So long as sexism is left unchallenged, and ‘casual’ references to violence are left unchecked and unsanctioned, women will continue to be held at arm’s length from the political process.”

Letters: Page 15