THE SNP’s most controversial Holyrood selection battle is at the centre of a new row after claims ‘dark money’ is helping to promote an ally of Nicola Sturgeon.

Former minister Marco Biagi said he had gone public with his concerns about the race for the party’s candidacy in Edinburgh Central after being ignored by SNP HQ.

He said rival Angus Robertson, a former SNP deputy leader close to the First Minister, could spend “unlimited” sums on social media ads because of flawed rules.

He suggested the party’s failure to impose a level playing field and cap spending during the selection gave Mr Robertson an unfair advantage over his grassroots rivals.

He said SNP HQ's "mishandling" of the situation was now "harming the party".

Mr Robertson has spent between £1000 and £1500 on Facebook adverts for his selection campaign since July in a bid to reach the local SNP branch's 1400 members.

Mr Biagi also complained that £1,270 of the £2,790 Mr Robertson has been raised from a crowdfunder appeal for the internal selection race had been given anonymously. 

This includes three anonymous donations of £250 and one of £400.

Mr Biagi, who was the MSP for Edinburgh Central from 2011 to 2016, stood down, and is now trying to stand again in the seat, said he had raised his concerns about the frontrunner repeatedly.

He said he had written to National Secretary Angus MacLeod and SNP chair Kirsten Oswald, but they had failed to respond. 

Although Mr Biagi did not name Mr Robertson, the examples he highlighted were those of the former Moray MP and SNP Westminster leader.

Mr Biagi said: “The ongoing mishandling of the current process for selecting SNP candidates for next May’s elections is harming the party. 

“The SNP prides itself on being a democratic organisation that affords opportunity to all members to participate. But this is not the impression currently being given.

“If the party’s National Executive Committee wants to restrict Dominic Cummings tactics or dark money donations they could do it any time. And they should. 

“All the work that has been done to ensure gender equality and disabled representation is wasted if candidate selections are left tilted towards those with the richest friends.

“SNP candidates should be raising money to unseat our opponents, not each other. 

“Every donation spent on an internal selection is one less available for campaigning on our shared objective of independence.

"In the 2018 Depute Leadership election paid social media advertising was limited by party rules. Why not now?

“I have raised this internally and it has gone nowhere. 

“I have exhausted internal channels and so with the greatest reluctance I am taking my concerns public so that members will know what is going on. I just believe ordinary party members want to see a level playing field – is that so much to ask?”

The SNP has repeatedly complained about the use of ‘dark money’, funds whose origins are unknown or unclear, when it benefits other parties, notably the Tories.

The row is the latest to hit the SNP’s selection contest in Edinburgh Central.

The seat is currently held by former Scottish Tory leader Ruth Davidson, who is moving to the House of Lords in May, leaving behind a wafer thin majority of just 610 votes.

The plum vacancy attracted two of the SNP’s big hitters, Mr Robertson, who lost his Westminster seat in 2017, and Joanna Cherry QC, the MP for Edinburgh South West.

With Mr Robertson an ally of Ms Sturgeon, and Ms Cherry close to Alex Salmond, the contest became a proxy battle between the First Minister and her estranged predecessor.

In July, the SNP’s ruling body controversially changed the party’s rules in what was widely seen as an attempt to stitch-up the race for Mr Robertson.

The National Executive Committee decided any sitting MP would have to give up their Westminster seat if they were selected for Holyrood, before the 2021 election.

Former SNP Westminster deputy leader Kirsty Blackman objected, saying it meant any MP interested in moving to Holyrood would have to make their staff redundant.

Ms Cherry pulled out of the race complaining it was “particularly unreasonable” to put her staff out of work in the middle of a economic crash caused by the pandemic.

Mr Biagi then entered the face alongside SNP activist Lee-Anne Menzies.

Mr Robertson, who yesterday became the first candidate in the country to launch an online hub for local members to get in touch, said: “I’m pleased to be using modern technology to communicate effectively with SNP members in Edinburgh Central.

“The selection rules are very clear in limiting our efforts through a website and social media outreach, which is exactly what I and other candidates are doing. 

“Fundraising is an essential part of modern selection and election campaigning and will be particularly important for the SNP in competing with the Tories to win in Edinburgh Central. 

“I believe I have the best all-round campaigning and candidate skills to help the SNP win."