Opposition politicians have reacted in fury after Nigel Farage said the Brexit Party won't contest the 317 seats won by the Conservatives at the last general election.

In an announcement, Nigel Farage said he would focus on Labour seats insisting he still wants to see Brexit Party MPs elected to hold Mr Johnson to account if he wins a majority.

He added: “It’s not easy, but how do we hold Boris to his promises? That’s the key to this isn’t it? That’s the key to whether this strategy actually works.”

He continued: “The way we keep Boris Johnson to his promises is we have to start to win some of these seats. That’s what we need to do in this election.

READ MORE: Boris Johnson given major boost as Nigel Farage says Brexit Party won't contest Tory-held seats 

First Minister Nicola Sturgeon tweeted: "Any form of Brexit that is acceptable to Nigel Farage will be deeply damaging for Scotland. Makes it all the more important to get rid of Boris Johnson’s Tories, escape Brexit and put Scotland’s future into Scotland’s hands. #GE209 #VoteSNP "

She added: "The Tory party has now effectively become the Brexit party. The SNP is the main challenger in all of their Scottish seats. Defeating the Tories here will help deprive Boris Johnson’s increasingly extreme and right-wing party of the majority they crave."

Meanwhile, Lib Dem leader simply tweeted: "The Conservative Party are the Brexit Party now."

Naomi Smith, the chief executive of pro-EU campaign group Best for Britain, accused Brexit Party leader Nigel Farage of having “bottled it” and intensified calls for Remainers to vote tactically.

READ MORE: Brexit Party will not contest 317 seats won by Conservatives at general election 

“Farage has bottled it and hung most of his own candidates out to dry,” she said.

“But by standing down Brexit Party candidates across the country, it’s now more important than ever that Remainers use their votes wisely.

“Our best chance of stopping a nightmarish government delivering a hard and damaging Brexit is voting tactically.”

Labour Party chair Ian Lavery said the Brexit Party decision to stand down candidates in Tory-held seats was part of a bid to satisfy US President Donald Trump and privatise parts of the NHS.

“This is a Nigel Farage and Boris Johnson alliance with Donald Trump to sell out our country and send £500 million per week from our NHS to US drugs companies,” he said.

“We urge voters to reject this Thatcherite 1980s tribute act, which would lead to more savage Tory attacks on working class communities. Our NHS is not for sale.”

Green Party election candidate and former leader Caroline Lucas tweeted: “Nigel Farage doesn’t need to stand against Conservatives because under Boris Johnson, the Conservatives have morphed into the same narrow sect as Brexit Party.

“This is the alliance Trump wanted. We must resist delivering Trump the result he wants too.”