The Liberal Democrats have called for the public debate on genetically modified crops to be delayed to coincide with the results of farm scale trials.

Speaking ahead of the publication of a Science Review report on Monday, rural affairs spokesman Andrew George questioned the timing of the series of debates across the country.

"The note of caution expected in the scientific review is hardly unexpected but sends a strong message to the government," he said.

"There simply isn't enough scientific evidence to reassure people that GMOs are safe for them or the environment.

"It is difficult not to be cynical about the timing of all this. The scientific review is being published just one working day after the GM nation debate has closed.

"The findings from the government's farm scale trials will not be published until September, so why didn't they postpone the scientific review and public debate to take this into account?"

George also said that there would be no demand for GM produce.

"It is clear that retailers don't want to market the stuff, the Downing Street strategy unit last week admitted that there was no market for it, and I would certainly warn farmers not to touch it with a barge pole unless they want to face a public relations disaster," he added.

"Decisions on GM should be based on sound science, not 'quick', 'make do' or 'hasty science'.

"If ever a political decision required caution, then this is it. Without adequate science in place we run the serious risk of taking an irreversible decision in haste, which we could regret at our leisure for many years to come.

"Only when issues of liability, the farm scale trials and human health impact studies have been completed and reported, will it be appropriate to revisit GMs.

"The government must rethink GM and face down pressure from the biotech giants and the United States and not be forced into making a hasty decision."