MP Lisa Cameron defects from SNP to Conservatives

Lisa Cameron did not rule out standing down and triggering a by-election

The SNP's Lisa Cameron has announced her defection to the Conservatives.

The East Kilbride, Strathaven and Lesmahagow MP was facing a selection contest to remain as the SNP's candidate at the next general election.

She said she quit because of a "toxic" culture in the SNP's Westminster group.

Prime Minister Rishi Sunak and Scottish Tory leader Douglas Ross both welcomed Dr Cameron to the party, while SNP leader Humza Yousaf called on her to step down to allow a by-election.

Mr Yousaf said her defection was "the least surprising news I've had as leader of the SNP" and that she should now do the "honourable thing".

"To see somebody who claims to have supported Scottish independence cross the floor to the Conservative and Unionist Party betrays the fact that she probably never believed in the cause in the first place," he added.

He said he was confident the SNP could win any by-election in the seat.

• Voters in East Kilbride react to MP's deflection

• SNP MPs face challengers in selection battles

• SNP MP 'can't rule out forcing a by-election'

Rishi Sunak, meanwhile, said he was "delighted" to welcome a "brave and committed" MP to his party.

"Lisa is right that we should aim to do politics better, with more empathy and less division and a dedication to always doing what we think is right," he said.

Dr Cameron, a former NHS clinical psychologist, said she had received support from Mr Sunak after her mental wellbeing deteriorated in recent weeks, but had no contact from the SNP leadership.

She rowed back on her support for Scottish independence, describing it as divisive. She said she would instead focus on "constructive policies".

The MP claimed previously that she had been "ostracised" by the SNP after speaking out over the handling of allegations against former Westminster chief whip Patrick Grady.

At the time, Dr Cameron did not rule out standing down and triggering a by-election if she did not win the SNP nomination.

The MP, who was challenged by party staffer Grant Costello, had been due to find out the results of the selection contest on Thursday.

Rishi Sunak said he was "delighted" to welcome Dr Cameron to the Conservatives

SNP Westminster leader Stephen Flynn said her claims of being ostracised "didn't reflect" his experience of the situation in Westminster.

Dr Cameron's announcement comes after the SNP were defeated heavily by Labour in the Rutherglen and Hamilton West by-election last week.

In a statement, 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."

'Healing divisions'

The MP said she was "particularly grateful" to the prime minister, praising his "positive, inclusive leadership".

She went on to claim families, including her own, have "experienced significant division regarding the issue of independence".

Dr Cameron added: "This has taken its toll and I have come to the conclusion that it is more helpful to focus my energies upon constructive policies that benefit everyone across the four nations of the UK, and to move towards healing these divisions for the collective good."

The defection means the Conservatives now have 353 MPs, including seven from the Scottish Tories, while the SNP have 43.

Eight SNP MPs have confirmed they are stepping down at the next election, including deputy group leader Mhairi Black and former Westminster chief Ian Blackford.

As defections go, this is about as breathtaking as they come. The SNP and the Conservatives are seen as polar opposites in Scottish politics - especially on the issue of Scottish independence.

The SNP exists to pursue separate Scottish statehood. The clue to the Conservative and Unionist party's commitment to keeping the UK together is in its name.

For Lisa Cameron to switch from one side to the other is an unexpected coup for Rishi Sunak and a damaging display of SNP disunity as Humza Yousaf prepares for his first annual conference as party leader.

Changing party between general elections does not require a by-election. Dr Cameron is allowed to continue as a Tory MP without the public getting a say.

Her chances of re-election as a Conservative if she stands again do not look good. The Tories were the third placed party in East Kilbride, Strathaven and Lesmahagow in 2019.

Dr Cameron has said she will stand down at the next general election, which is expected next year, according to Mr Ross.

The Scottish Tory leader said there had been discussions with the MP for "some time" before she defected.

"Lisa can see that the Conservatives and Rishi Sunak are offering the leadership for Scotland and the whole of the UK in contrast to the attitude of Humza Yousaf and the SNP which is to focus on independence above all else," Mr Ross told BBC Scotland News.

Due to Westminster boundary changes, her seat will change to East Kilbride and Strathaven at the next UK poll.

Scottish Labour MP Ian Murray said: "This bizarre move shows that the SNP is falling apart before our eyes."

Scottish Tory leader Douglas Ross said talks were held with Lisa Cameron for "some time" before she defected

Following the MP's previous threat to call a by-election, party sources told BBC Scotland News they did not recognise her bullying claims and that there was unhappiness in the party.

Concerns were previously raised about a leaked letter that Dr Cameron had written to the Scottish Secretary Alister Jack, which appeared to back his decision to block the Scottish government's controversial gender recognition reform legislation.

And in 2019, she raised concerns that she could be deselected after being one of only two SNP MPs who voted against lifting Northern Ireland's abortion ban.

There was also said to be unhappiness within the local party about the number of taxpayer-funded overseas trips Dr Cameron has taken in her role as a parliamentarian as well as a view she is "not a team player".

'Slap in the face'

A source from the East Kilbride SNP branch said the defection came as came as "no surprise" but would be a "slap in the face" for members.

"It is clear she lost faith with members and had very little support," they said.

"East Kilbride and Strathaven deserve an SNP candidate who will stand up for the local community, championing independence as the solution to getting rid of the Tories."

Following Dr Cameron's announcement, the SNP confirmed that Mr Costello had secured the nomination for East Kilbride and Strathaven.

Alison Thewliss - whose Glasgow Central constituency is disappearing due to the boundary review - lost out to frontbench colleague David Linden in Glasgow East.

However, she was selected to stand in Glasgow North, which is being vacated by Mr Grady.

SNP Europe spokesperson Alyn Smith successfully saw off a challenge in Stirling and Strathallan, as did former chief whip Brendan O'Hara in Argyll, Bute and South Lochaber.