The Scottish Greens will not field candidates in the two most marginal seats in the entire UK - both of which are held by the SNP.

Green party associations in North East Fife and Perth and North Perthshire have chosen not to stand general election candidates, in a break with the strategy set out by the Scottish party.

Launching the Scottish Greens' campaign in South Queensferry on Friday, co-leader Lorna Slater said the Greens would contest more than 20 seats around Scotland.

But the party's plans have faced an online backlash from pro-independence supporters after the SNP's candidate for Perth and North Perthshire, Pete Wishart, said they would split the independence vote.

Wishart fended off the Tories by just 21 votes to win in the 2017 election and highlighted that the last time the Greens stood in the seat, in 2015, they won more than 1000 votes.

Now, with the local Green association's decision to withdraw, the other candidates currently expected in the contest with Wishart are the Scottish Conservatives' Angus Forbes, Peter Barrett of the Scottish Liberal Democrats and the Brexit party's Stuart Powell, with Scottish Labour yet to announce its candidate.

And in North East Fife, where the SNP's Stephen Gethins beat the Lib Dems by just two votes in 2017, the Greens have also decided not to run.

Gethins is currently pitted against the Lib Dems' Wendy Chamberlain, Labour's Wendy Haynes and the Tories' Tony Miklinski in his bid to retain the country's most marginal seat.

The Greens have also opted not to run in Angus, but vowed to campaign against Conservative incumbent Kirstene Hair who the local party says "has a voting record that stands against everything we are for".

Hair will face Dave Doogan of the SNP, Liberal Democrat Ben Lawrie and Labour's Monique Miller in the election.

The SNP has welcomed the decision by the Greens not to stand in its most marginal seats, with Wishart saying he is "grateful" to the local Green party, but the Tories slammed the moves as "cowardly".

The Scottish Greens said the decision on whether or not to stand candidates is one taken by local associations, not by the central party.

They are independent from the Green party in England and Wales, which last week entered into a "Remain alliance" in dozens of seats south of the border with the Lib Dems and Plaid Cymru.

The Scottish party said it would not enter any similar pacts and says its top priority is putting pressure on "all of the establishment parties" to tackle climate change.

A spokesman for the Scottish Greens said: "The decision about whether to stand in individual seats is for local Green branches and are taken for a number of reasons including looking at resources for fighting the 2021 Holyrood election.

"But all over the country Scottish Greens will be putting pressure on all the establishment parties to recognise the urgency of the climate emergency.

"This is the first general election since UN climate scientists gave us just ten years to turn it around and the loudest and clearest way to demand climate action is to vote Scottish Green."

On their decision in his constituency, the SNP's Wishart said: "I am really grateful to the Perth and North Perthshire Greens for not standing a candidate against me.

"I hope that I can repay this generosity with my work in parliament."

A Scottish Conservative spokesman said: "This is a cowardly move from the Scottish Greens, who are clearly terrified of upsetting their paymasters in the SNP.

"The SNP has repeatedly played Patrick Harvie and it is getting embarrassing to watch."

It comes as Nigel Farage's Brexit party announced it would not field candidates in any Conservative-held seat across the UK.

The Brexit Party leader said he had taken the "difficult decision" not to contest the 317 seats held by the Tories at the last election amid fears it could lead to a hung parliament and a second EU referendum.

The announcement was welcomed by the Prime Minister who said it was recognition that only the Conservatives could "get Brexit done".

The Scottish Liberal Democrats branded the move proof of an "unholy alliance" between the Brexit party and the Tories.

MSP and the party's campaign chair Alex Cole-Hamilton said: "Nigel Farage standing down shows the Conservatives and the Brexit party are now one and the same.

"Johnson's hard-right Brexit takeover of the Tory party has now been endorsed by both Trump and Farage.

"Ruth Davidson's attempts to detoxify the Scottish Conservatives are now utterly dead in the face of this unholy alliance.

"Moderate Conservatives should join the Liberal Democrats in stopping Brexit, stopping independence and building a brighter future."