THE SNP has called on an MP who left the party to join the Tories to resign and spark a by-election.

Lisa Cameron, MSP for East Kilbride Strathaven and Lesmahagow, quit the SNP today and joined the Scottish Conservatives.

The MP released a statement outlining her decision.

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She said: "I do not feel able to continue in what I have experienced as a toxic and bullying SNP Westminster group, which resulted in my requiring counselling for a period of 12 months in Parliament and caused significant deterioration in my health and wellbeing as assessed by my GP including the need for antidepressants.

"I will never regret my actions in standing up for a victim of abuse at the hands of an SNP MP last year, but I have no faith remaining in a party whose leadership supported the perpetrator's interests over that of the victims and who have shown little to no interest in acknowledging or addressing the impact."

Before she quit Cameron was facing a challenge for re-selection as the SNP candidate for the seat from party worker, Grant Costello.

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The SNP said Cameron’s  constituents would be “appalled”.

A spokesperson for the SNP said: “The people of East Kilbride, Strathaven and Lesmahagow will be appalled they are now represented by a Conservative and Unionist MP.

“Lisa Cameron should now do the right thing and step down to allow a by-election.

“Her constituents elected an SNP MP not a Tory, and they deserve to have the democratic opportunity to elect a hard working SNP MP who will put the interests of Scotland first. On a personal basis, we wish her well.”

The Tories welcomed their new MP.

Douglas Ross, Scottish Conservative leader, said: “I’m delighted to welcome Lisa Cameron to the Conservative Party.

“Like many ex-SNP supporters, she has realised that her former party is hopelessly divided under Humza Yousaf and incapable of focusing on the real priorities of the Scottish people.

“Lisa took a principled stand in supporting the victim in the Patrick Grady case, when her party took the side of the disgraced MP. For doing so, she has been shamefully and inexplicably mistreated by the SNP.

“I look forward to working with Lisa, who recognises the Conservative Party and the Prime Minister are focused on the issues that matter to people in Scotland and across the UK.”