However, if global wastage of food is cut, then production will not have to grow at such a rate to meet demand, the UK government's chief scientific advisor, Professor Sir Bob Watson told the Oxford Farming Conference.

Sir Bob told the conference that recent reports such as the Foresight Report and the study by Sir John Beddington's Commission on Sustainable Agriculture, showed that the current food production system is unsustainable.

He said there is huge wastage in present food production and there are growing concerns over the excessive use of nitrogen and fertilisers to produce food.

"We are not feeding the world sustainably and at the same time one billion people go to bed each day hungry, and that is not acceptable," said Sir Bob.

He told the conference that there will be a growing demand for better food in developing and progressing countries such as China, but food production is also in competition with land, water and energy usage. He added that climate change is also having an effect on food production, with drought and floods in some regions.

He said that taking no action is not an option and there is a need for a change in attitude right along the food production chain.

"Food demand will double in the next 50 years, but you don't need to double production if you get rid of wastage," he said.

However, he said the challenge is to do it with less labour and to increase yields with less land.

He said that food production only needed to be increased by between 30 and 60 per cent if waste is cut.

He said that in developing countries a vast amount of the food that is produced is wasted either on the farm or in transport to market, whereas in developed countries such as the UK and the US, the majority of the wastage comes in the home, in retail and in food service.

While reducing waste will be one part of meeting the challenge of feeding a growing population, research and development also need to be addressed.

He said that it will be necessary to access new technology in seeds, agricultural chemicals, irrigation and to address weather changes, as climate change will also be critical in meeting food demands.

"Science will be critical in meeting then challenge of climate change, biodiversity loss and increased pollution," he said.

Prof Watson said to meet these global challenges it is necessary to build food stocks, trust and cooperation and to champion and non-integrated approach to food security and support sustainable intensification as well as press for trade liberalisation in the common agricultural policy and common fisheries policy.

He said that agriculture has to be at the centre of sustainability and diversification.

He added that it is necessary to manage the ecosystems better and improve food production with a smaller footprint.

To achieve innovation along the whole food production chain, science and technology will be critical.