Boris Johnson has seen his projected Commons majority slashed from 80 to just 12 seats in a week as Jeremy Corbyn’s Labour party eats into the Conservatives’ lead, a poll of polls has revealed.

The survey - based on almost 10,000 voters - shows Jeremy Corbyn closing the gap on the Tories in the same way as Theresa May’s lead collapsed after her manifesto launch and her refusal to appear in TV debates.

Labour is squeezing the Liberal Democrats by gaining Remain voters who see the party as the better prospect to block Mr Johnson’s bid for a rapid Brexit, according to Electoral Calculus which uses socio-economic and past voting data to take account of individual constituencies’ profiles.

Martin Baxter, founder of Electoral Calculus, said the stalling in the Tory vote could explain why Mr Johnson used a speech on Friday to “beat the drum” for working class Brexit votes with pledges on immigration and state aid to protect jobs.

It follows warnings this week by Mr Johnson’s chief of staff Dominic Cummings that a hung Parliament remains “a very real possibility” with Tories and Labour much closer than the polls suggest.

The Electoral Calculus data - which follows all three parties’ manifestos and Mr Corbyn’s “car crash” interview with the BBC’s Andrew Neil - shows the Tories on 41.9 per cent, down from 43 per cent this time last week.