Nicola Sturgeon has been accused of plotting to install Jeremy Corbyn in 10 Downing Street in exchange for getting a second independence referendum.

Ruth Davidson said the First Minister had offered a “progressive alliance” between the SNP and Labour because Mr Corbyn has said he would be “absolutely fine” about staging another independence vote.

But Ms Sturgeon wrote off the Labour leader’s chances of becoming Prime Minister, either by winning a majority or with the help of her party, describing the possibility as “pie in the sky”.

Speaking at First Minister’s Questions, the SNP leader told MSPs opinion polls show Mr Corbyn “ain’t going anywhere near number 10 Downing Street on his own or with the help of anybody else.”

She argued that Scots should vote SNP to provide the strongest opposition possible to “out-of-control” Tory government and warned traditional Labour supporters there was no “safe” tactical vote for the Conservatives.

Ms Sturgeon appeared to concede that the Conservatives will win the general election, and the only question is by how much, only a day after she raised the prospect of an unofficial alliance between Labour, SNP, Liberal Democrat and Green MPs to keep the Tories out of power.