There is “genuine concern” that the Scottish Conservatives will not unite behind the next leader amid a contentious contest, a former head of the party has said.

Tensions have reached a new level in recent days, with contender and former deputy leader Meghan Gallacher making a complaint to the party about one of its own MPs.

The complaint is understood to revolve around an accusation that Berwickshire, Roxburgh and Selkirk MP John Lamont threatened her career.

The candidate is reported to have been concerned she would be de-selected ahead of the Holyrood election in 2026 after the call.

Mr Lamont – who has announced his support for Russell Findlay in the contest – strongly denied the allegations, which he described as “defamatory and false” and added: “I am now considering further action including legal options.”

In the wake of the tensions, former leader Jackson Carlaw told the Daily Telegraph he is worried the party may struggle to come together behind the leader after the contest, which also includes MSP Murdo Fraser.

“There is genuine, genuine concern that the party is going to find it very difficult to come together after this leadership election, which we all have to do, because we have three excellent candidates,” he said.

“One of them will be elected leader. But the atmosphere is now becoming so toxic that I am appealing to people as a former leader, and as the oldest Conservative MSP, as someone who has not declared for any of the candidates, who is not tribally aligned, for people to wind their necks in now and allow the balance of this election to be conducted without further rancour and to be prepared to work together on the other side of it.”

He added: “That is not going to be the basis on which we can all pull together in a relatively short period of time to fight a major election where we’re the only party who are actually saying anything distinct or different, and where there has to be a proper alternative put to the people of Scotland.”

The former leader said it is “absolutely incumbent” on members to “stop this now”.

In a post on X, formerly Twitter, on Monday, Mr Fraser described Mr Carlaw’s intervention as “wise words”.

“The sexism, misogynistic bullying, threats of legal action and constant blue-on-blue attacks we have seen must end,” he said.

“Our members and supporters are rightly angered by this behaviour. This needs to be a contest of ideas and vision.”