The development of a British GM crop industry will deliver little or no economic benefits, a Downing Street report has concluded.

The Strategy Unit study will come as a blow to ministers who have argued that Britain must allow GM crops to be commercialised for economic reasons.

The report, leaked to newspapers over recent days, said that Britain could prosper by providing non-GM foods.

However, the overall economic benefits will depend upon public attitudes towards the new technology, which thus far has been strongly sceptical.

"The Strategy Unit has explored the economics of GM crops in a very open and transparent manner," said environment minister Elliot Morley.

"I am particularly pleased that they involved experts and stakeholders from all shades of opinion to ensure there was balance and rigour when examining this important issue.

"The report highlights that GM crops are one area in which GM technology has significant potential to contribute to the UK's future economic prosperity and sustainability.

"But it also points out that GM crops are just one possible tool for achieving our goals - important advances in crop production will also come from conventional and organic techniques."

The minister called for wider views on the report's conclusions and recommendations.

"The report sets out a range of potential futures for GM crops in the UK," he added.

"These helpfully illustrate the trade-offs that will be involved whatever approach the UK adopts to GM crops over the next 10 to 15years.

"But quite rightly, the report reiterates that consumers and retailers will play an important part in shaping the future role for GM crops. We would very much welcome views and comments on the Strategy Unit's report and conclusions."

The economic report is one of three studies currently underway into the GM issue.

A science review will be released within weeks to inform the nationwide public debate that is now underway.