By-elections are different to general elections. Voters understand they are electing a single Member of Parliament, not a government. They often take place in mid-term, at a time when prime ministers are at their least popular. Local issues regularly dominate. They ought, therefore, to come with a health warning.
And yet this does not feel like the usual mid-term blues. The Conservatives, having lost the Wakefield by-election to Labour last year and Tiverton and Honiton to the Lib Dems on a swing of 29.9 per cent, could face defeat in a further three in the space of a month: Uxbridge and South Ruislip in West London, Selby and Ainsty in North Yorkshire and Somerton and Frome in Somerset.
