Party activists who want to see an immediate switch to a new Scottish currency are to oppose the leadership’s plans to retain the pound for an indefinite period after a Yes vote.

This is line with the recommendations of the party’s recent Sustainable Growth Commission and means a new currency would only be adopted after six key fiscal tests are met.

Finance secretary Derek Mackay is leading the push for this, along with party deputy leader Keith Brown. They have a joint motion at the party conference later this month to make a new Scots currency official party policy after independence after the tests are met, replacing the idea of retaining the pound as part of a currency union with the UK.

Derek Mackay is leading the push for a new currency. Picture: contributed

Former East Lothian MP George Kerevan is leading the opposition to this approach, calling for the tests to be scrapped and a new currency to be adopted in the first parliament after independence. Other amendments will also be debated by SNP members later this month, including shifting to a separate Scots currency immediately after independence that would be pegged to the UK pound, backed by MP Ronnie Cowan.

Mr Brown said: “With independence, we can pursue a currency policy that’s right for Scotland, maximising opportunities as a successful European nation in a global economy.

“We’re looking forward to a positive, mature discussion over our country’s future at our upcoming Spring Conference where different views can be expressed.

“Of course, opponents of self-government for Scotland would rather spurn the opportunities of independence in favour of a disastrous Brexit and continued chaos under Westminster rule.”

The currency issue was widely seen as being a weak point of the case for independence during the 2014 referendum after the UK Government ruled out the prospect of a currency union that underpinned the policy.

The Sustainable Growth Commission, lead by former SNP MSP Andrew Wilson, set out six tests including the credibility of Scotland’s economic record at that stage and the level of its reserves, as well as whether it would improve trade.

Mr Kerevan launched the Campaign for an Independent Currency (CIC) last month, with a warning over the commission’s proposals with claims that it would mean Scotland could be forced to keep the pound indefinitely and the fledgling country would effectively be a “vassal state”.

Pamela Nash, chief executive of Scotland in Union, said the latest development showed that SNP splits over currency had “deepened”.

She said: “This is now a major challenge to Nicola Sturgeon.

“We have Nationalists who want to put salaries, mortgages and pensions at risk in the medium term, Nationalists who want to put them at risk in the short term and Nationalists who want to put them at risk immediately.

“The fact that an SNP MP has backed an irresponsible and reckless proposal to immediately scrap the pound and adopt an independent currency pegged to sterling is alarming. It’s now clear that the only way to save our pound and build a successful economic future is by remaining in the UK.”

SNP facing grassroots challenge over changes to independence currency proposals