Boris Johnson’s election hopes have been hit by an emerging deal between Labour and the SNP to block a poll before the next Brexit delay.

Jeremy Corbyn met Ian Blackford, the Scottish nationalists’ Westminster leader, today to agree that the election must take place only after Britain has secured another extension from the European Union.

The pact, which could lead to the parties uniting to call a confidence vote on Mr Johnson as soon as Monday, came after the resignation of his brother.

Jo Johnson’s decision to resign as universities minister and as an MP overshadowed what had been intended to be the prime minister’s campaign launch in Wakefield, Yorkshire.

In a statement on Twitter Jo Johnson said: “It’s been an honour to represent Orpington