AN informal “Better Together” pact is working together to unseat SNP Westminster leader, according to reports.

The Tories and Labour are said to be holding back to allow LibDem candidate Craig Harrow to take the Ian Blackford's constituency.

A senior Tory told The Times: “Conservatives on the ground will be sorely tempted to vote LibDem in order to get rid of Ian Blackford.

"It would be some embarrassment for SNP to lose two Westminster leaders in two elections.”

Labour also reportedly said they would resist putting too much effort into fighting for the constituency.

READ MORE: Boris Johnson makes threat over SNP's control of Scottish NHS

A Scottish Labour source said that they were seeing “a groundswell of support for the LibDems”.

Harrow was a friend of Charles Kennedy, the former LibDem leader, who held the constituency for decades until being unseated by Blackford in 2015 in what was a bad-tempered campaign.

The LibDems have long accused the SNP of behaving badly and running a negative and hostile campaign against Kennedy, who died not long after at the age of 55 following his long battle with alcoholism.

Alex Cole-Hamilton, the LibDems’ General Election campaign chairman, said: “It would be a huge setback for the nationalists if they were to lose their Westminster leader for two elections in a row,” he said.

An SNP spokesman said: “This election is a straight fight between the SNP and the Tories.

"As a hardworking local MP, Ian Blackford is looking forward to taking the Tories on.

"Only a vote for the SNP is a vote to beat the Tories, stop Brexit and protect Scotland’s right to choose its own future.”