THE First Minister is preparing to publish a key document setting out a fresh economic case for independence, as expectation grows of a referendum before 2021.

Nicola Sturgeon told 500 guests at an SNP fundraising event in Glasgow that she would be unveiling the party’s Growth Commission report in the new year.

To loud applause she told the audience at the dinner on Friday night that the report would set out the economic strategy for building a prosperous independent Scotland.

The Growth Commission was set up in September last year as part of a long-awaited summer initiative to speak to undecided voters in an attempt to win over more support for independence in the wake of the EU referendum. It is chaired by former MSP Andrew Wilson and its membership includes senior figures from business, economics, politics and academia.

A key part of the commission’s work has been to make recommendations for policy on measures to boost economic growth and improve Scotland’s public finances – both currently and in the context of independence; and also how savings could be made in the event of independence by pursuing different defence policies such as dropping support for Trident.

It is understood the report, running to more than 100 pages, is divided into three sections, with one dedicated to fiscal policy, a second to inclusive growth and a third to currency.

The Yes side’s 2014 position on a currency is now seen as a weakness in their case for independence as it took the view Scotland would carry on using sterling – only to be undermined when then chancellor George Osborne said an independent Scotland could not use the pound.

Previous reports have suggested the Growth Commission will recommend that an independent Scotland should adopt a separate currency.

Last night a source told The National he believed the report would back a “gradualist” move to a new currency – in line with other countries that had become independent.

The source added: “The problem last time is that the pro-independence side just talked about currency, it didn’t talk about some of the structural questions – like, how you would set up the institutional framework necessary? What has been given to Nicola is a thoughtful piece on what needs doing in terms of the currency.

“This sets out, whatever the choice of currency is, how are we going to support that in the marketplace?; what are the institutional mechanisms to make it work and give it the best start?”

The report will also highlight the UK tax system, which it will argue is overly complex and which officials estimate is responsible for an under-collection of at least £36 billion a year.

It is understood the SNP’s commission will recommend an independent Scotland introduces a simpler system – along the lines used by other smaller European nations such as Denmark – with fewer loopholes allowing people to avoid paying tax which would therefore increase the tax take.

Immigration is addressed too in the report with plans set out to boost the number of investors moving to Scotland from overseas.

One option being discussed is to reduce the level of funds foreign investors must have from £10 million to less than £5 million in a bid to attract more entrepreneurs.

“Scotland could benefit from people with still significant sums but with a lot less than £10 million,” a source said. “There are lots of things we can do policy wise that would not increase the costs to the Scottish Government but would significantly increase the amount of investment in entrepreneurship in Scotland and in turn economic growth.”

A spokesman for the SNP said the report was likely to be published in the new year. He added a substantial part of it considered Scotland’s economic situation now, post Brexit – and not only as it could be under independence.

The Growth Commission has also been addressing the transfer of pensions payment arrangements in an independent Scotland.

Announcing the Commission’s membership Sturgeon last year said: “Scotland is a wealthy country with resources and talents that many other countries can only dream about.

“The challenge, however, lies in closing the gap between our potential and the reality. We want to strengthen our foundations and seek to identify the very best opportunities for Scotland’s economy to flourish.”

Membership of the SNP’s Growth Commission include Glasgow University’s Iain Docherty, Professor of Public Policy and Governance, Kate Forbes MSP, Andrew Hughes Hallet, Professor of Economics and Public Policy, University of St Andrews, Roger Mullin, the former MP, and Catherine Schenk, Professor of International Economic History at University of Glasgow.