BEN Gill, president of the NFU, warned that climate change was one of the biggest challenges to be faced, with first estimates saying the unusually long hot summer across Europe had resulted in lost food production totalling 13bn euros.

"It is a lot of money, but that does not include the cost to society or industry," said Mr Gill, who said the River Danube - an important trade route - had been closed for many months.

Closer to home, the Government needed to spend another £4bn on improved flood defences to prevent the centre of London from being flooded. "The Thames Barrier has been raised more times in the last year than since it was built," he said.

The Met Office reported that temperatures had risen by one degree in the last century - but that had all occurred in the last decade.

Over the next 75 years it predicted temperatures would rise by a further five degrees.

There would be long hot summers, short winters and concentrations of heavy rainfall and floods. More reservoirs would be needed.

Mr Gill said Government would have to pay farmers to use land as flood plains to help households close to rivers.