Anti-EU populist leader Nigel Farage said Monday he will field hardline Brexit candidates across Britain despite fears he could deny Prime Minister Boris Johnson a majority in next month's election.

Farage wants to sever all ties with the European Union and calls Johnson's divorce deal agreed with Brussels last month a "sellout" of the hopes of Britons who triggered Brexit in a 2016 referendum.

The Brexit Party chief said Johnson's ruling Conservatives could pay dearly for rejecting his offer for a "non-aggression pact" in the December 12 snap election.

Farage wants to sever all ties with the European Union
Farage wants to sever all ties with the European Union AFP / Adrian DENNIS

"There will be no Brexit without the Brexit Party," Farage told a London rally of hundreds of Brexit Party candidates standing in the country's third election in four years.

"Here's the problem with the proposition Boris Johnson is putting to the British people -- it is not Brexit," he said to a standing ovation.

Farage's promise of a swift and complete break from the 28-nation bloc brought him victory in European Parliament elections that Britain was forced to take part in due to Brexit delays in May.

Anti-Brexit activists demonstrate outside of the the Houses of Parliament
Anti-Brexit activists demonstrate outside of the the Houses of Parliament AFP / Tolga Akmen

The Brexit Party's ratings fell sharply after Johnson seized power in July on a "do or die" pledge to deliver Brexit by October 31.

But Johnson was forced to accept another postponement after failing to push through his withdrawal terms through parliament in time.

His hopes of securing the majority needed to see his deal ratified and Britain leave by the latest January 31, 2020, deadline are now being clouded by Farage's year-old group.

Johnson has ruled out a pact with Farage
Johnson has ruled out a pact with Farage AFP / Adrian DENNIS

The Brexit Party leader's offer to Johnson came after US President Donald Trump -- a "no-deal Brexit" backer who supports both men -- endorsed a collaboration.

Numbers game

Johnson has until a November 14 deadline to register candidates to still accept the Brexit Party's "clean break" terms, according to Farage.

But the prime minister said Friday he has "ruled out a pact with everybody because I don't think it's acceptable."

Farage called Johnson's decision "truly regretable".

AFPTV / Arman SOLDIN

He also rejected accusations from the Conservatives that he was splintering the pro-Brexit vote.

"We won't split the vote because we'll be the only party offering to leave the EU," Farage declared.

Even the most ardent backers of Brexit have attacked Farage for his decision to contest the vote.

Conservative pro-Brexit lobby leader Steve Baker said Johnson "will not succeed if Nigel Farage creates a hung parliament by dogmatically pursuing purity".

"Whatever Nigel's motives, he risks being the man who threw away Brexit," Baker told the Daily Telegraph newspaper.

Farage insisted that his party's main target will be the pro-Brexit voters who traditionally support the main opposition Labour Party.

He estimated that nearly five million Labour Party members who voted for Brexit in 2016 could be lured into voting for his party.

But most analysts think that past voting records show the Brexit Party potentially hurting the Conservatives more.

"The Brexit Party drew 72 percent of its support from 2017 Conservatives and 17 percent from 2017 Labour voters," Jon Mellon and Geoffrey Evans of the British Election Study research group wrote in a report.

"In Labour-held seats, this gap narrows slightly to 64 percent Conservatives and 24 percent Labour voters."

Yet analysts doubt that Farage's party will be able to win more than a handful of seats.

He refused to answer repeated question from reporters Monday about how many seats he thought he might win.