Alex Salmond has admitted the SNP would use an “overwhelming” general election victory in Scotland to try to force a second independence referendum only two days after Nicola Sturgeon played down the link.

The former First Minister said the Nationalists would try to use a big win north of the border to “reinforce” their demand for another independence vote at a time of the Scottish Parliament’s choosing.

He argued that Theresa May’s refusal to allow another vote as soon as autumn next year will “crumble” even if the Prime Minster wins a Commons majority of 150 across the UK.

The Conservatives said Mr Salmond has “let the cat out of the bag” after Ms Sturgeon faced widespread mockery for arguing that the election campaign has nothing to do with independence.

She made the claim on Monday in the wake of opinion polls showing the SNP shedding thousands of votes and up to 10 seats to the Tories.

But the First Minister posed during a campaign stop on Wednesday in Stirling sitting on a motorbike plastered with “Yes 2” stickers backing a second referendum.