COMPANIES and investors should not be "unduly concerned" about independence but Scotland will struggle to recreate the Stock Exchange it lost in 1973, according to a report which looks at an imagined "Scotsie 100" index.

Identifying 100 Scottish company stocks currently listed in London, Paul Marsh of London Business School and Scott Evans of Walbrook Economics compared their "Scotsie 100" with a parallel "Rest of the UK" index over the last 60 years.

They found that £1 invested in the Scotsie 100 in 1955 would have grown to £648 today (with dividends reinvested), a 5.7 per cent increase in real (inflation-adjusted) terms. However, £1 invested in the rest of the UK would have grown to £1,168, a 6.8 per cent increase.

But this included the "devastating" impact of the RBS and HBOS banking crisis, without which the report states Scotland out-performed the rest of the UK.

The academics state: "Despite the many uncertainties, we do not believe that investors in 'Scotsie 100' stocks should be unduly concerned, or be making contingency plans to rebalance their portfolios."

They observe that almost all countries which have achieved independence over the last generation have sought to create their own stock exchange, but the case for Scotland doing the same is "more nuanced," given the importance of the Stock Exchange in London.

It would be better, say the authors, to encourage a venture capital and private equity industry in Scotland.

Tony Banks, chairman of Business for Scotland, said: "One of the big problems Scotland faces is the gravitational pull of London and the south-east of England for UK businesses, which is a vital reason why we need the economic powers of independence so that we can exert a powerful pull in the direction of Scotland."

A Better Together spokesperson said: "Being part of the UK single market is essential for Scottish firms to thrive.

"Companies based here have barrier free access to a market of more than 63 million people in the UK, rather than just five million people in Scotland. Where is the sense in putting a barrier between Scottish firms and their customers elsewhere in the UK?"