The former SNP MP Lisa Cameron has accused powerful people in her old party of turning a blind eye to bullying and threats of violence against opponents.

Dr Cameron, who defected to the Conservatives last year, said “shadowy figures” and anonymous social media accounts were used to harass and menace people.

“Let me say to my former party, political arguments should never be made through intimidation and threats of violence,” she told the Scottish Tory conference in Aberdeen.

The East Kilbride MP, who was first elected in 2015, defected to the Tories in October after accusing her Westminster colleagues of creating a “toxic and bullying” culture.

She said she was ostracised because of her religious beliefs and views on sex and gender.

Humza Yousaf called it a “betrayal of her constituents” and urged her to resign as an MP.

Dr Cameron, who is now a parliamentary private secretary to Scottish Secretary Alister Jack, introduced Scottish leader Douglas Ross’s main speech at today’s conference.

Despite the Tories at Westminster being riven by faction fighting and plotting, she began by saying: “After years in the toxic SNP, it is so refreshing to have a place in a party where we support each other. Where we work together as a team.”

She then gave a lengthy account of her treatment after her defection.

She said: “Leaving the SNP has not been easy.  And I don’t mean that because I miss my former party at all - far from it. 

“But Nationalists and their supporters have tried to make my life a living hell and that of my family ever since I left.

“I have had death threats. I had one person say they wanted to brick me in the street and others say they wanted to burn me and my family alive. 

“I now have had to have panic alarms fitted into my home and parliament have helped to strengthen and reinforce the doors of windows in my house.

“In the week that I left the SNP I even had to take my family to a safe house. That’s where politics in Scotland has descended to.

“I knew that leaving the SNP would mean that I would become a target for the very, very worst nationalism. 

“But the bile and vile threats that I have received are beyond even my wildest imagination.

“Rather than engaging in the substance of issues, Nationalist trolls resorted to bullying.

“And I'm sure that very many of you here today have experienced this too.

“Far, far too often, figures within the party have turned a blind eye to this  - or worse, have seemed complicit in it.”

The written text of her speech was more blunt, referring to “senior figures" within the SNP who turn "a blind eye to this or, at worst, are complicit in it".

Dr Cameron went on: “Those who did not conform to nationalist orthodoxy in Scotland, or have tried to challenge positions of those in power, are dismissed, they’re degraded and they’re shouted down in public. 

“Whilst in private shadowy figures and anonymous accounts have used social media to harass and menace people, to bully them.”

She concluded by arguing voters to reject her old party.

She said: “This year we face a general election. Right across Scotland, more and more people, like me, are seeing the true face of nationalism.

“They can see that in so many ways it is ugly and divisive. That it thrives on splitting Scotland, in turning our country inwards and against itself, into two camps: us and them. 

“When we all know that Scotland is so much more diverse than that.

“The SNP deserve to lose, and they deserve to lose big.”

An SNP Spokesperson said: “There is absolutely no place in politics for intimidation or threats, and we continue to wish Lisa well on a personal basis.

"The people of East Kilbride, Strathaven and Lesmahagow elected an SNP MP, not a Tory - and we believe Lisa Cameron should have stepped down to allow a by-election and let her constituents have the democratic opportunity to elect a hard working SNP MP who would put their interests first.”