Biofuels must be added to transport fuel to combat climate change, and fears over their environmental value and influence on food prices should not discourage the government from ordering an increase in their use, a group of leading agricultural scientists said on Friday.

The scientists mounted their defence of biofuels as environmental groups stepped up their campaign against them ahead of the introduction next week of the Renewable Transport Fuels Obligation (RTFO), under which petrol companies must ensure 2.5 per cent of the vehicle fuel sold in the UK is made up of biofuels.