When launching the Scottish National Party’s election campaign, Nicola Sturgeon said the word ‘Tory’ 20 times in 20 minutes. For much of her political lifetime, it has been used by the SNP as the dirtiest word in Scottish politics. Nationalists have long liked to portray the Conservatives as the successors to Edward Longshanks: an occupying army with little affinity for the people they were trying to govern.