A leading consumer group raised the concern as the government prepares to announce the exact location of four new GM crop test sites.

The whereabouts of the sites are being made public on the Environment Agency's Website on Monday, despite the recent destruction of crop fields by environmental protesters.

Meanwhile, reports that up to 12 sites in Scotland have been identified for such trials next year have been denied by government officials in Edinburgh and London.

A spokesman for the Scottish Executive said that any new sites would have to be given approval by Scottish ministers.

At the same time, the National Consumer Council (NCC) has warned that poor labelling of GM foods is leading consumers to believe that they are not being given vital information.

Big concern

The NCC said 85% of the 1,000 people questioned in a survey were worried that they were being denied access to the full facts on goods ranging from GM foods to digital TV.

BBC Environment Correspondent Margaret Gilmore: "The new crops will be the first of many"

NCC director Anna Bradley said: "GM foods are one of the big concerns at the moment because food is not labelled clearly enough and the government is not acting promptly on this issue.

"People are not confident that decisions on GM foods are being made in their interest," she said.

The NCC called on the government to beef up the Freedom of Information Bill going through Parliament so that shoppers would have access to the data they wanted.

The four new GM crop trial sites are part of a new wave of trials of oilseed rape and maize which will total 75 by next year.

Trials condemned

They are to begin in the autumn at Market Rasen, Lincolnshire; Bingham, Nottinghamshire; Glentham, Lincolnshire; and Hemel Hempstead in Hertfordshire.

The BBC's Robert Pigott: "Not just the farmers who are unhappy"

They will go ahead without extra security measures after Government ministers rejected industry pleas for secrecy on big farm-scale trials to stave off sabotage by environmentalists, such as a recent Greenpeace attack in Norfolk.

The trials have already been condemned for being based on what one MP called "incompetent" scientific standards.

Alan Simpson, the Labour MP for Nottingham South, told BBC Radio 4's Westminster Hour: "All the scientific benchmarks currently in use are at best haphazard and at worst incompetent.

"We have to stop treating a revolutionary science as though it was just a different form of cake decoration."