Climate change is expected to worsen the food shortage

New chief science adviser, Professor John Beddington, said the crisis could be as serious as climate change and may hit sooner.

The world's 6.5 billion population is expected to reach nine billion by 2050.

This, combined with growing consumption as poverty is alleviated, will put huge pressure on food supplies, he said.

No simple solution

Professor Beddington said there would be a huge knock-on effect as economic growth lifts people out of poverty in countries like China and India.

He told BBC News: "Something is actually happening out there for very good reasons, namely that poverty is being alleviated.

"To some extent we are actually trying - and properly so - trying to eliminate poverty. Now as poverty is eliminated big changes in consumer demand occur."

Climate change is expected to worsen the problem, reducing rainfall and affecting crop growth.

There is a real, fundamental problem emerging in food policy that, frankly, has been under-recognised

Professor Tim Lang, City University

Added to this, efforts to tackle climate change - by using biofuels instead of fossil fuels - are taking more land away from food production.

Professor Tim Lang of City University has welcomed the chief scientist's effort to draw attention to a relatively neglected issue.

He told BBC News: "I welcome it, that a chief scientist would do this is a sign that he's expressing what a lot of us out there feel is a very big shift in the food economy.

"There is a real, fundamental problem emerging in food policy that, frankly, has been under-recognised."

Professor Beddington said there would be no simple solution and is calling for more agricultural research as a matter of urgency to help tackle the problem.