A pressure group in the US is pressing the Government's Food Standards Agency to ban a meat substitute made in the region.

The Center for Science in the Public Interest (CSPI), a US lobby group, alleges that Quorn, which is made at Marlow Foods' plant in Stokesley, North Yorkshire, causes vomiting and diarrhoea.

The CSPI wants Quorn - popular with vegetarians - removed from supermarket shelves until health checks have been carried out on the product.

The group claims it had recent reports of more than 130 adverse reactions to Quorn, 85 per cent of them in Britain.

Quorn, made by fermenting fungal protein in a glucose solution, has been on sale in Britain for 15 years by Marlow, which employs 360 people and earlier this year was named the frozen and chilled exporter of the year.

A spokesman for Marlow maintained that adverse reactions to the food were extremely rare.

"Only one in 146,000 people have had an adverse reaction to Quorn and that is much lower than other foods such as soya or dairy products," he said.

The food agency said it was still satisfied by previous assurances from the company on health issues, but would look at the complaints.

But damage may already have been done to Marlow and its parent company, AstraZeneca, amid reports that the allegations have frightened off potential buyers of Marlow Foods.

One company, Hg Capital, is thought to have already pulled out of the bidding over the concerns.