Conservative hopes are rising that they can this week repeat the double by-election trick of losing one but holding one.
In July, they lost the safe Tory seat of Selby and Ainsty in Yorkshire, which Labour gained with its second biggest swing from the Tories ever. But on the same day, the Tories held Uxbridge and South Ruislip, a marginal seat that had been held by Boris Johnson.
There is another brace of by-elections this Thursday. They are both safe Tory seats – Tamworth in Staffordshire, and Nadine Dorries’s former seat of Mid Bedfordshire. Labour needs a 22 per cent swing to gain Tamworth, which is less than the 24 per cent swing it achieved in Selby, but the situation in Mid Beds is complicated because the anti-Tory vote is split between Labour and the Liberal Democrats.
