The Scottish Greens will put pressure on the SNP Government to ditch its support for the expansion of Heathrow Airport on climate grounds - labelling their Holyrood partners’ position as “reckless”.

The Scottish Government remains committed to supporting a third runway being built at Heathrow Airport, with SNP ministers signing a memorandum of understanding in 2016 that supported the expansion bid which included a pledge of 16,000 new Scottish jobs and 75,000 new flights between London and Scottish airports.

The plans to build a third runway at Heathrow have been delayed by legal challenges and the Covid pandemic. 

Aviation is excluded from the Bute House Agreement of co-operation between the Scottish Government and Scottish Greens, meaning the two partners can differ on policy.

Read more: SNP may use 'higher tax for more polluting aircraft' in aviation duty

But the Greens are set to push their SNP colleagues to ditch the support of further airport expansion as the Scottish Government draws up its final aviation strategy.

It comes after a rift between the two parties in government over Humza Yousaf's decision to freeze council tax next year.

Two years ago, an independent report, drawn up by Element Energy on behalf of the Scottish Government, found that domestic and international aviation emissions will need to be cut by 33% if 2030 legal climate pledges are to be met.

But the Scottish Government is yet to publish its final aviation strategy.

The pressure from the Greens comes as it’s revealed that Heathrow Airport has ramped up its lobbying of MSPs.

Lobbying records show that over the last 12 months, airport bosses held 16 meetings with MSPs from the SNP, Conservatives and Labour – including a discussion with SNP Net Zero and Transport Secretary, Mairi McAllan.

Records also show that at last year’s SNP conference, Heathrow Airport officials met with Humza Yousaf, Shona Robison, Keith Brown and then-net zero secretary Michael Matheson.

Read more: Aviation demand in Scotland needs to fall by one third by 2030 to hit climate aims

Airport bosses have also held meetings with Douglas Ross, as well as several Tory MSPs including Maurice Golden who met with Heathrow bosses at the Holyrood magazine awards in September when he won the ‘green giant’ award for his environmental work. 

Anas Sarwar has also met with airport officials twice in the last 12 months, as well as Labour MSPs Colin Smyth and Neil Bibby.

Despite setting ambitious climate goals to reach net zero by 2045 and cut 75% of carbon emissions by 2030, the Scottish Government remains in support of expanding Heathrow.

A government spokesperson told The Herald that “Scotland will benefit from this major infrastructure project which will bring significant job creation and investment opportunities to Scotland”.

But Scottish Greens environment spokesperson, Mark Ruskell, said that "expanding Heathrow would be reckless”.

He added: “If we allow our aviation sector to keep expanding indefinitely then it will make attempts to tackle climate change impossible.

"Particularly when it comes to domestic travel, there must be efforts to encourage frequent business travellers to use low-carbon rail rather than aircraft.

"The Scottish Government is yet to finalise its aviation strategy. We will always make the case for it to be fully aligned with our climate goals."

A report from independence statutory advisers, the Climate Change Committee (CCC), warned that Scotland was lagging behind other parts of the UK in cleaning up transport and has been “unwilling to consider measures” like restricting aviation growth.

In a response to recommendations from the CCC, the Scottish Government said its aviation strategy “will consider opportunities for decarbonising aviation in Scotland”, which officials said will build on a pledge “to making the Highlands and Islands the world's first emissions free aviation region in the world”.

Read more: Analysis: Warm words won't cut it as SNP's window for climate action running out

The Scottish LibDems have long campaigned against the Scottish Government supporting a third runway at Heathrow.

Scottish LibDems leader, Alex Cole-Hamilton, has stressed that “expanding Heathrow is simply not compatible with Scotland’s climate change commitments”.

He added: “This expansion alone would produce more emissions than some small countries.

“Scottish Liberal Democrats are clear that we should be focusing on cheaper, better and faster rail services instead and spreading the benefits of international connections to regional airports rather than centralising yet more of our economy in the South East.

“It's time for the Scottish Government to rip up its Heathrow deal and finally put some muscle behind Scotland’s pledge to tackle the climate emergency after years of missed targets and opportunities.

“Scotland cannot save the planet alone but it should be using every opportunity to show real leadership and secure green jobs for the future.”

But the Scottish Conservatives have warned that the UK-wide infrastructure of Heathrow, which is crucial to Scottish trade, must continue to be supported.

Scottish Conservative transport spokesman, Graham Simpson, said: “The SNP might not like the fact that most Scots want to remain in the UK and share in its wider infrastructure, but even they recognise the huge boost Scotland would receive from Heathrow’s expansion, and have backed it.

Read more: Scotland's climate plan could be delayed after Sunak's net zero U-turn

“They should resist the dogmatic and unrealistic calls from their Green coalition partners and other extremists and instead acknowledge the huge technological strides the airline industry has made in reducing its climate impact.

“That shared way forward is the best course for promoting growth and reaching achievable net zero targets.”

A Scottish Government spokesperson said: “The decision to allow Heathrow expansion was taken by the Westminster Government and UK Parliament.

“We have been clear that when the expansion of Heathrow Airport, the UK’s only global hub airport, goes ahead then it must deliver benefits for all UK nations.

“The memorandum of understanding with Heathrow Airport ensures that Scotland will benefit from this major infrastructure project which will bring significant job creation and investment opportunities to Scotland.”