THE SNP have hit back at a think tank over its interpretation of a report commissioned by Nicola Sturgeon setting out a new economic case for independence.

Head of communication Fergus Mutch described a video made by Common Weal on the Growth Commission as inaccurate. He highlighted a film the group made about a “solidarity payment” proposed in Andrew Wilson’s blueprint published last year. It would go towards previous UK debt and shared commitments such as international aid.

Publicising the video on Twitter, the Common Weal said: “Second film in our series ‘Know Your Growth Commission’ focuses on the ‘solidarity payment’ SNP members are being asked to vote for. It’s a humiliating proposal handing over power, decision making, & billions of £ to the UK.Vote for REAL independence.”

Mutch responded: “Sorry @Common_Weal, you’ve got this entirely wrong on every count. I’d encourage @theSNP members to look very carefully at the resolution being brought to Spring Conference and to refer to the Sustainable Growth Commission report itself if in doubt. But the points made in this film are inaccurate.”

The row broke out after a resolution was put down to the SNP’s conference next month asking members to back the central recommendations of Wilson’s report. In the video, Common Weal urged SNP members not to support the resolution. It said Wilson’s report would mean Scotland would accept the total debt the UK wanted it to take without negotiation and that the new state would pay a total of £5.3 billion a year “forever”.

In a series of tweets Mutch said: “We’re not accepting debt without negotiation. 2014 confirmed UK has continuing liability for all debt. By definition, indy Scotland will start with zero. But indy Scotland could agree solidarity payment to help service interest & provide a positive start to negotiations.

“We’re not handing away £1.3bn in foreign aid money after independence. SGC report... uses this as an example of where we may wish – if mutually beneficial to both UK and Scot Govs – to continue in shared international programmes for a transitional period.

“So by saying an independent Scotland would have to pay Westminster £5.3bn a year forever ... Common Weal is making cynical conclusions & completely misrepresenting the findings of @sgcommission & the resolution being brought to Conference.”

Mutch’s response was picked up by Wilson, who suggested Common Weal was worse than the Tory Brexiteers in the European Research Group. He wrote: “At least the ERG are actually members of the Conservative Party.”

Jonathon Shafi of Common Weal said: “CW is one of the best things to have come from 2014. Constantly producing new policy ideas. Truth is I suspect Andrew never really liked the new grassroots emerging from 2014. Would prefer elites dealt with it all.”

Open Democracy’s Adam Ramsay said: “It’s not healthy to imply the other side don’t have a right to participate because they aren’t members of the governing party.”

Former SNP minister Marco Biagi said: “I think [Wilson] is disputing what other people say his vision of independence is. And he’s right. That CW video of the Growth Commission takes a view of the text that is – as I now often euphemise on undergraduate essays – a novel interpretation.”

Common Weal said its video was accurate. It said: “We have been criticised ... for describing the annual solidarity payment as lasting “forever” but it is clear the commission does not see this as a short-term plan.

“It describes ... the debt aspect of the payment over the course of at least 30 years and the approach to “shared services” and Foreign Aid transfer are described as lasting for “a transitional or, indeed, an extended period.”