FEAR was a major factor in this election; fear of the SNP, that is.

David Cameron has made not about Europe, but the "nightmare", "chaos", "paralysis" of a left-wing Ed Miliband being helped into No 10 by an even more left-wing Nicola Sturgeon the central theme of the Tory election campaign.

From strategist Lynton Crosby's desk in Conservative HQ has emerged a continuous flow of Nat-bashing propaganda aimed directly at voters in the Lab-Con marginals of England.

It began with a poster of a tiny Ed Miliband popping out from a large Alex Salmond's top pocket. The ex-First Minister used the image to make political capital and tap the Tory nerve by suggesting - he who holds the balance of power, holds the power.

Cornflakes were being choked on from Tunbridge Wells to Totnes at the very thought that those nasty Scottish Nationalists could hold sway over Downing Street.

Then, after Ms Sturgeon was introduced to Middle England in the seven-cornered TV debate, Conservative fire was directed at the First Minister with a poster featuring her as a puppeteer, happily pulling Mr Miliband's strings.

When the Tory leader appeared on TV and made an off-the-cuff joke about Mr Salmond being a pick-pocket, another lightbulb appeared above Mr Crosby's head and within hours posters were being put up across English marginals, showing a sneaky, black-clothed ex-Nationalist leader trying to pick someone' s pocket.

Then, after a poll even suggested the SNP could take all 59 Scottish seats, another Conservative campaign poster appeared with Mr Miliband at the Commons despatch box with 50 Alex Salmonds, many smirking, seated behind him on the green benches.

If the Tories do get in and are able to form a government either on their own or with the help of friends in the Liberal Democrats and Democratic Unionists, then many within and outwith Mr Cameron's party might well conclude that playing the SNP card in England - "Ajockalypse Now!" as Boris Johnson put it - had worked.

Some will conclude that just as with the independence referendum last September, fear rather than hope will have won the day.