A leading UK scientist says he thinks genes from genetically-modified (GM) crops will inevitably escape into other plants.

He is Steve Jones, professor of genetics at University College, London.

Professor Steve Jones explains his concerns over genetically modified crops

In Leviathan, a TV programme to be shown on BBC Two on 14 April, Professor Jones looks at the creation 80 years ago of the original hybrid crops.

And in an interview with BBC News Online, he explains his concerns over GM crops today.

"People may be worried that GM food is not safe to eat. I think that's unlikely. But if it were true, we could easily find out.

"It's straightforward science. But evolution is not like that."

Inherently unpredictable

Professor Jones says it is impossible to predict what evolution will do, and draws a parallel between GM foods and antibiotics.

Is penicillin's fate a warning of where GM crops could lead ?

"If you had said in the 1940s that penicillin would be completely useless in parts of the world within 50 years, people would have thought you were mad.

"But you would have been right. Evolution picked up a gene and changed it, and now the bacteria are resistant to penicillin.

"We are doing more or less the same with genetically manipulated plants. Those genes are going to get out into other plants. Everybody knows that.

"And we have no idea what is going to happen."

Health risks dismissed

The prospect haunts Professor Jones. What would happen, for instance, if a gene that conferred resistance against insects escaped?

Professor Jones: We are experimenting with evolution

"Suddenly we have no insects. With no insects you have no ecology, no ecosystem, no pollinators, no flowers, God knows what.

"Now this probably will not happen. But it certainly might. With GM plants, we are doing something new. We are moving genes around to where they've never been before.

"And we don't seem to be considering the possibility that evolution may take advantage of those genes, as it has done previously, in ways that we don't like."

More rigour needed

He does not think the field trials planned to test the safety of GM crops are "really rigorous enough".

Steve Jones believes modified genes are certain to escape

"A tiny accident, one gene leaking out, can have massive consequences.

"Too much attention is being paid to a non-problem - are GM foods poisonous? They almost certainly ain't.

"But we have to be sure what we are doing before we go ahead, and I think we're going ahead far too soon."