Oil from algae, the microscopic plants that produce a green covering on the surfaces of ponds and neglected outdoor swimming pools, may soon be filling diesel pumps.

As crude oil has moved towards $100 (€70, £50) a barrel and sustainable alternatives are sought in a bid to reduce carbon emissions, researchers are investigating “second- generation” biofuels – those not made from food crops such as soya or corn. Scientists have found that, in terms of oil yield, algae could be the most efficient source of biofuel.