The formula for Conservative election victories in modern times has been to start with the southern middle classes, and then work northwards (geographically) and downwards (demographically). Under this formula, the Party would usually hold, say, Tynemouth. It might occasionally win Darlington, for example – as it did in the first great Thatcher landslide of 1983. It would never stand an earthly in Blyth Valley. We choose an example from the North East, but there are parallels elsewhere.