Number 10 given analysis that shows Johnson would perform worse than May in election

According to Amber Rudd’s special adviser, Jason Stein, the polling carried in the last two weeks tells Number 10 “we are looking at picking up roughly 295 to 300 seats”.

While it does not reveal the scenarios or questions asked, the results suggest that Johnson would fall short of the 325 needed for an outright majority, and would end up with a result smaller than the 318 seats Theresa May won in 2017, which in itself was a fall from 331 seats under David Cameron.

Boris Johnson currently has just 288 MPs after the prime minister sacked rebel MPs and there were further resignations.

It suggests that a general election would not resolve the Brexit impasse in the House of Commons.

Speaking to Sky News, Stein said: “Number 10 themselves will privately tell you, this will be a tough election, they’re not expecting this to be the land of milk and honey.

“It is just the simple fact that we’re going to lose seats in London, in the South West, in Scotland… They need to be replaced, they’re already 10 behind, we to win 35 seats in areas we’ve never won before just to break even.”

It comes as opposition MPs fighting to prevent a no-deal Brexit confirmed they would not back Boris Johnson’s second bid to secure an early election.

A spokesperson for the anti-Brexit campaign group Best for Britain said: “Boris Johnson’s terrible week just keeps getting worse.

“He knows he has united parliament against him, and he’s also seen data showing the country doesn’t back his undemocratic attempts to force through a damaging no-deal Brexit.

“The only reason the prime minister is looking for a general election now is because he knows parliament has him in a corner, calling his bluff to defy the rule of law.

“And if the prime minister does break the law, the case for Brexit to go back to the people in a final say will be clearer than ever.”