Ruth Davidson has warned the Scottish Conservatives against complacency after the first general election campaign opinion polls showed them on course for a remarkable electoral breakthrough, winning up to a dozen seats.

The Scottish Tory leader urged her party members to “work, work and work some more” after two surveys indicated that they are threatening the SNP in a series of rural seats including the Moray constituency of Angus Robertson, the Nationalists’ Westminster leader.

A Panelbase survey, commissioned by The Sunday Times Scotland, put support for the Scottish Tories at 33 per cent, an increase of an astonishing 18 points compared to the 2015 general election.

They currently have only one Scottish MP, David Mundell, the Scottish Secretary, but this would give them 12 seats including 10 from the Nationalists and one from Labour. This would be their best result in Scotland since Sir Edward Heath's government in the 1970s.

The poll recorded 44 per cent backing for the SNP, down six points on the 2015 election. This would still mean the Nationalists winning 45 of Scotland’s 59 seats.