Media playback is unsupported on your device Media caption Partick Harvie said no approach was made to the SNP over a "progressive alliance"

The co-convener of the Scottish Greens has defended his party's decision to field candidates in just three constituencies in the general election.

Patrick Harvie said it was "overwhelmingly about resources" and denied it was an attempt to thwart Conservative gains.

He told the BBC's Sunday Politics Scotland the focus on key seats was the best option for returning a Green MP.

He denied his party had offered to form a "progressive alliance" with the SNP.

The Greens had 32 candidates in the last general election two years ago, but failed to win any seats. They currently have six seats at Holyrood.

The party has announced that this time it will focus on getting Mr Harvie elected in Glasgow North and will also have candidates in Falkirk and the Edinburgh North and Leith seat.

Image copyright Scottish Green Party Image caption Maggie Chapman, left, recently suggested a "progressive alliance" with the SNP

Mr Harvie said the decision to fight in only three seats was taken by local branches.

He said: "All of them looked at the resources they had left after the seven national votes we've had including the Holyrood and local elections that we put huge amounts of resource and energy into - and they recognised this wasn't something they were able to do.

"Last time, two years ago in the 2015 election, we stood in about half the seats in Scotland and I regret honestly that we're not in a position to do that again this time or even get close to it."

Mr Harvie conceded that in some seats local branches would be contemplating how best to prevent Tory gains.

'Off-the-cuff' remark

But he insisted that his party, which backs Scottish independence, had not approached the SNP about forming a "progressive alliance" - despite it being suggested recently by his fellow Scottish Greens co-convener Maggie Chapman.

He said: "It wasn't something that the party had decided to do. Maggie was expressing a personal view in an off-the-cuff interview."

Asked what his message would be to Green supporters in the 56 seats where there will be no Green candidates, he said: "I think they should ask all the candidates the issues that are most important to them."

He added: "We have a stronger chance of getting a first Green MP at Westminster than we had in the 2015 election or any previous election because we are focusing our resources.

"Because we are not knocking on the doors of millionaires and billionaires to fund the campaign, but we are knocking on the doors of constituencies where we are campaigning and talking to people about investment in a sustainable future."

Tommy Sheppard, the SNP incumbent candidate for Edinburgh East, has previously called on the Greens to avoid splitting the pro-independence vote in key constituencies.

The decision to limit the number of Green candidates was criticised by the Scottish Conservatives who said they should withdraw from televised debates.

Scottish Conservative candidate Ross Thomson said the Greens were "pretty much admitting they aren't a political party any more".

The SNP, the Conservatives, Labour and the Liberal Democrats have each selected candidates in all 59 Scottish constituencies, while UKIP has said it is aiming to have more than 10.

For the first time, the Lib Dems have ensured there are female candidates in their top target seats.