GORDON Brown’s pro-union think tank is coming under pressure to reveal the source of a mysterious quarter of a million pound boost to their coffers. 

According to the latest accounts filed with Companies House, the group's assets increased from £5,386 in 2020 to £267,942 in 2021. 

A spokesman for the organisation said their funding came “via donations from among the many hundreds of individuals."

But the SNP’s economy spokesperson, Alison Thewliss called on the think tank to publish its full finances “in the interests of transparency."

Our Scottish Future was launched by Mr Brown in 2019 with the aim of outlining a “progressive future” for Scotland in the United Kingdom.

However, he "transformed" it into "a campaigning movement" in May 2021, days after the SNP won their fourth term in government on a manifesto containing a pledge to hold another independence referendum.

Mr Brown said he was relaunching the group to make “the positive, progressive and patriotic case for Scotland in Britain.”

He urged people to join him. 

The change in purpose occurred in the same financial year as the swell in assets. 

Ms Thewliss said clarity about Our Scottish Future's income would be in the public interest.

She said: "This is a huge jump in a short space of time, and people, including those who support and donate to the organisation, will rightly want to know where the £255,000 has come from.

"I would urge Our Scottish Future to publish its finances in the interests of transparency, and as an example to all organisations."

A spokesman for Our Scottish Future said:

"Our Scottish Future exists to make the positive case for Scotland as part of the UK. We seek to represent the views of those who both oppose and support independence by promoting the idea of a stronger Scotland in a reformed UK.

“Founded by Gordon Brown, the organisation now has a growing number of supporters, including some of the most respected figures in Scottish public life.

"They include the former leader of the Scottish Green party Robin Harper, the former senior civil servants Professor Jim Gallagher and Philip Rycroft, and the Scottish cancer clinician Professor David Kerr.

“Our Scottish Future and its office bearers have met all the legal obligations for disclosure and will continue to meet these in the future. 

"All our funding comes via donations from among the many hundreds of individuals who have signed up to support us and who back our objectives.

"Those donations have helped us to maintain a small staff, and to commission research on how Scotland and the UK can cooperate better on economic growth, the environment, and health.

"It has also helped us to stage a major conference next month together with the Glasgow Chambers of Commerce on how the Glasgow and West of Scotland economy can become Britain’s Northern Superpower.

“We hope this constructive work is adding to Scotland’s political debate at a time when too many political players in Scotland are focussed solely on attacking the other.”

“We are incredibly grateful to those who have supported us in 2022 and it gives us confidence that we can grow further in 2023 as we seek to set out a more positive and progressive vision for both Scotland and the UK.”