Boris Johnson launched his general election campaign with a rally in Birmingham, where he attacked Labour’s Brexit stance as a “Bermuda Triangle” barren of intelligence, and compared Nigel Farage to “candle sellers on the dawn of the electric lightbulb”.

But Labour party deputy leader Tom Watson stole the headlines as he announced his decision to stand down as an MP in the middle of Mr Johnson’s speech, citing reasons “personal, not political” and a desire to campaign about ”the public health challenge facing our country”.

Boris Johnson’s campaign had earlier been thrown into disarray as Alun Cairns quit as Welsh secretary after being accused of “brazenly lying” about his knowledge of an allegation that his former aide sabotaged a rape trial.

The Tories were also accused of doctoring footage to falsely suggest Labour’s Sir Keir Starmer was unable to answer a question about Brexit, while James Cleverly was brutally “empty-chaired” after missing a Sky News interview.

Mr Johnson was criticised for comparing Jeremy Corbyn’s “hatred” of wealth creators to the persecution of the Kulaks – a group of landowning peasants killed by Stalin in the 1930s.