Support for Scottish businesses was found to vary

The report found that the cost per job created ranged from �2,000 in Edinburgh to �26,000 in Lanarkshire.

Businesses generally reported positive responses to the help provided by the Scottish Enterprise Network.

But Audit Scotland said it needed firm evidence that the �40m of public money devoted to this effort was well spent.

Scottish Enterprise has spent the millions in funding over the last three years on providing help to firms which are judged to have big potential for growth.

Scottish Enterprise accepts the needs for a more consistent approach to its account management service Robert Black Auditor general for Scotland

The Audit Scotland report called for greater consistency in the way that local enterprise companies, the local arms of Scottish Enterprise, select the potential high-fliers in the first place.

It said Scottish Enterprise should also investigate why the benefits gained from the process show big variations across the local enterprise companies.

The findings came in a report by Robert Black, the auditor general for Scotland, on Scottish Enterprise's "account management" service to potentially high-growth businesses.

Under this approach, the local enterprise companies (LECs) pick out high-flying firms in their area and allocate an account manager to each one.

Cash support

Direct cash support can also be given by the local enterprise companies, but Mr Black's report found the advice by the business account managers often had more impact than financial assistance.

Firms supported in this way were "generally positive" about the scheme, he went on.

But Scottish Enterprise and the LECs had yet to implement a consistent approach to selecting companies.

Robert Black called for proof of value for money

The LECs did not always hold "consistent and comprehensive evidence" to show that the firms being helped met the aid criteria.

The LECs should also improve their checks on whether the benefits of the scheme were being delivered.

Mr Black's report said that while the firms increased their workforces, results varied widely, with the cost per job up to 13 times higher in one area than in another.

And although the help was meant for viable firms and projects with a good chance of being self-sustaining within a few years, nearly two thirds of the firms had been supported by their LEC for at least five years.

Mr Black said: "Scottish Enterprise accepts the needs for a more consistent approach to its account management services.