Boris Johnson has stamped on Nigel Farage’s call for a pact to deliver a no-deal Brexit, vowing the Tories will fight for every sat at the next election.

The leader of the Brexit Party is pushing for a formal alliance to “rout” pro-EU parties, claiming: “A non-aggression pact could win a majority of 60 to 100 seats.”

The idea would see the Brexit Party agree not to stand against Tory candidates fully committed to a no-deal, in return for the Conservatives giving Mr Farage’s party a clear run in Labour-held seats.

But, speaking on his trip to the United Nations, Mr Johnson vowed: “We will be contesting the next election when the Labour Party – the opposition – finally summon up the nerve to have an election.

“We will be contesting the next election as the Conservative party and not in an alliance, or a pact or a coupon, a receipt.”

Pressed on whether the Conservatives would field a candidate in every seat, the prime minister replied: “Of course.”

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It is the first time Mr Johnson has explicitly ruled out a pact with Mr Farage, in what will be seen as a big boost to opposition parties hoping the looming election will topple him.

The Brexit party is confident of eating into the Tory vote if the election is held with the UK still in the EU – with Mr Johnson having failed to deliver the “do or die” Brexit he pledged for 31 October.

With a divided pro-Brexit vote, the prime minister could even be under personal threat in his West London constituency of Uxbridge, where he defends a slender majority of 5,034.

Mr Farage has privately threatened to stand a high-profile candidate there, as well as against other vulnerable Tories such as Iain Duncan Smith – whose majority is just 2,438 in Chingford.

At the weekend, he said “the only way” for Mr Johnson to get away with breaking his promise of leaving the EU on Halloween was to do a deal with the Brexit Party.

Private polling in 10 key Midlands marginal seats, which the Tories need to win, showed that if Mr Farage gave Tory candidates his personal endorsement, 67 per cent were more likely to back them, he claimed.

“If you add up our polling position, between us we are on 47 per cent,” Mr Farage told The Sunday Express.

En route to the UN on Sunday, Mr Johnson warned there would be no “New York breakthrough” to deliver a Brexit deal, admitting to “clear difficulties” ahead of talks with EU leaders.