'Radical rethink' urged over food

The assessment showed that future global food supplies could be threatened by the impacts of climate change on where crops can grow, increases in the incidence of animal diseases and water shortages.

It also issued a warning over the depletion of fish stocks around the world, as well as the impacts on the natural world of expansion of crops grown for fuels and a growing population eating more.

But with rising yields in cereals and uncropped land that can be brought into production, the UK can contribute to global food security, the assessment said.

Across the world, it has been estimated that production will have to rise by 70% by 2050 to feed a global population of nine billion.

The Government has committed almost £1 billion to ensuring food security for poor countries and funding research into sustainable agriculture in the developing world, according to the study.

Mr Benn said he wanted British farmers to produce as much as possible, but they needed to do so in such a way that took account of a changing climate and the need to tackle global warming emissions - to which agriculture is a significant contributor.

He said: "Last year the world had a wake-up call with the sudden oil and food price rises. While we know the price of our food, the full environmental costs and the costs to our health are significant and hidden. We need a radical rethink of how we produce and consume our food.

"Globally we need to cut emissions and adapt to the changing climate that will alter what we can grow and where we can grow it. We must maintain the natural resources - soils, water, and biodiversity - on which food production depends. And we need to tackle diet-related ill health that already costs the NHS and the wider economy billions of pounds each year."

The assessment is published alongside an update on last year's Food Matters report from the Cabinet Office on rising food prices, the problems of unhealthy eating and the environmental impacts of what we eat.