The three main party leaders entered their final few days of campaigning yesterday with Boris Johnson keeping goal in Heald Green, Cheshire, Jeremy Corbyn serving at a cafe in Barry, Wales, and Jo Swinson playing tennis in Reading

Jeremy Corbyn is poised to resign as Labour leader and hand over to John McDonnell if he loses the general election, according to allies.

In secret WhatsApp messages, seen by The Sunday Times, union officials claim that McDonnell is exploring plans for him to replace Corbyn until a leadership contest, which could be delayed until autumn next year.

Under the plans, Corbyn would resign on Friday and make way for McDonnell, who would immediately appoint his protégée Rebecca Long-Bailey as shadow chancellor. He would launch parallel reviews of Labour’s election defeat and the party’s leadership structure, while demanding his successor be named at party conference next September.

According to a party insider, Corbyn has told friends that he is unwilling to stay on as leader…