Trident has become a political weapon in certain constituencies

One constituency where the Tory attacks about a possible deal between Labour and the SNP work very well is Barrow and Furness, where Labour’s John Woodcock is standing for re-election. The seat includes shipyards where the new Trident submarines would be built, and so any suggestion that Labour might scale back its commitment to Trident is hugely potent for the local campaign.

A couple of days after Michael Fallon launched his poorly-received attack on Ed Miliband, in which the Defence Secretary warned that the Labour leader had stabbed his brother in the back and could therefore quite easily stab the UK in the back by forging a deal with the SNP, a letter on the same subject went out to voters in Barrow. It was sent to 20,000 households, and was from Fallon. It warned of the threat of a Labour-SNP deal to Trident.