Speaking to delegates at the Royal Agricultural College's Contribution to the Quality of Life conference in Cirencester on Monday, Mr Gummer said interest in carbon footprints was set to get bigger, giving farmers "a better chance" of selling local produce.

"The new battle will be in local provision and sourcing," he said. "We only need one occurrence of the drought or deluge climate change creates for global food supplies to be affected.

"People are beginning to realise local food is important, but people are in for an easy life so we need to make it easier and cheaper for people to be good."

Mr Gummer said farmers were already doing a huge amount to promote local foods in response to climate change, but said there was "more to be done".

"Farmers have to redouble their efforts to explain what they do. They need to build closer relationships between farming and urban areas."

Mr Humphrys agreed farmers needed to make more effort to get politicians and consumers to understand the importance of local food in relation to climate change.

"Use local media to get your voice heard," he said. "Farmers tend not to spread their message and instead stay inside and grumble. You should use us, that's the way the media works.

"Local food is key. It is achievable and the goals are easy for the public to understand.

"Not enough is being done at the moment, but if you manage to generate local interest, politicians will listen. Politicians change if they think they will lose popular support."