The Brexit Party has announced that it will not stand candidates in the 317 seats won by the Conservatives at the 2017 general election.
Party leader Nigel Farage said standing candidates across the country could increase the chances of another EU referendum taking place.
But he said the party would stand against all other parties – and focus on taking seats off Labor.
It had vowed to stand more than 600 candidates. The Commons has 650 seats.
Launched in April, the Brexit Party does not hold any Commons seats – but the party was the clear winner in the UK’sEuropean elections in May.
Prime Minister Boris Johnson welcomed the move, calling it “a recognition that there’s only one way to get Brexit done, and that’s to vote for the Conservatives”.
But Tory chairman James Cleverly added there was still a “danger” the Brexit Party could split the vote in target seats, leading to the election of MPs who could “frustrate the Brexit process”.
Explaining his decision to supporters in Hartlepool, Mr Farage said Mr Johnson had recently signalled a “big shift of position” in his approach to Brexit.
He cited a pledge by the PM not to extend thetransition periodthat would follow the UK’s departure from the EU. This would see Britain sticking to the European Union’s rules on issues such as freedom of movement until December 2020.
Mr Farage also said he was encouraged by recent commitments from Mr Johnson to seek further divergence from EU rules in a post-Brexit trade deal.
He added that this was a “huge change” from the kind of trade pact that had been planned under former PM Theresa May.
‘Unilateral Leave alliance’
Labor leader Jeremy Corbyn said Donald Trump “got his wish” when Mr Farage announced his electoral strategy.
He said the Brexit Party leader was offering a “Trump alliance” that would lead to “Thatcherism on steroids” and threaten the future of the NHS.
The US president hadpreviously urgedthe Mr Farage to team up with Boris Johnson, saying they would be “an unstoppable force”.
Liberal Democrat deputy leader Sir Ed Davey said Mr Farage’s decision “shows the Conservatives and the Brexit Party are now one and the same”.
Mr Farage had previously offered to not to stand candidates against the Tories in certain seats if the prime minister changed aspects of his Brexit deal.
But the proposal was rejected by Boris Johnson, who said deals with “any other party” would “risk putting Jeremy Corbyn into No 10 “.
Polling expert Sir John Curtice said it was “pretty clear” the Tories would benefit from Mr Farage’s move, although it was “not as big a boost as we might imagine”.
He said Mr Farage’s strategy would not provide assistance to the Tories in marginal seats they are hoping to take off Labor.
“Nigel Farage’s offer doesn’t really give the prime minister the price he would really want, which is a free run against the Labor Party,” he told BBC News Channel.
Mr Farage said he had “genuinely tried” to forge a so-called “Leave alliance” with the Tories, but his efforts had gone nowhere.
“In a sense we now have a Leave alliance, it’s just that we’ve done it unilaterally,” he added.
Mr Farage has already confirmed he willnot be standing himselfin the election, saying he wanted to concentrate on helping his party’s candidates.
Mr Farage will not contest seats where the Tories are running – a “big step in the right direction”, says one Cabinet minister.
“It really clarifies it for a significant subgroup who were still very torn,” says another member of the government.
Hypothetically, the decision by the Brexit Party leader makes it notionally easier for the Tories to keep seats they hold already.
But it’s a million miles away from giving them a clear run.
Pro-Remain election pact
Scottish National Party leader Nicola Sturgeon said the Conservatives have “effectively become the Brexit Party”.
She added that defeating the Tories in Scotland “will help deprive Boris Johnson’s increasingly extreme and right-wing party of the majority they crave”.
Anti-Brexit parties Plaid Cymru, the Green Party and the Liberal Democrats have agreednot to stand against each otherin 60 seats across England and Wales.
Their pact means that, in Wales, two of the parties will agree not to field a candidate, boosting the third candidate’s chances of picking up the Remain vote.
In England, it will simply be a two-way agreement between the Lib Dems and the Greens.