The Tory victory in Hartlepool, with a swing of 16 per cent and the biggest increase in a governing party’s vote in any by-election since 1945, is a terrible blow to Labour hopes that the choice of Sir Keir Starmer would soon stem their rot. What happened in what was a safe Labour seat — it was Peter Mandelson’s in New Labour’s heyday — is that voters who backed the Brexit party in 2019 switched to the Tories.