E. coli bacteria, which are commonly associated with food poisoning, have been genetically modified by scientists to produce fuel that is almost identical to diesel.

Their research is partly funded by Shell, and they say that if the process could be scaled up, this synthetic fuel could be a viable alternative to fossil fuel.

Professor Love of Exeter University said the significance of their discovery was that unlike other biofuels such as ethanol, this fuel is a complete substitute for fossil fuels.

Most forms of biodiesel and bioethanol that are currently used are not compatible with modern engines, and are blended at a volume of 5% or 10% into fossil fuels before they can be used.

Professor Love said: “Rather than making a replacement fuel like some biofuels, we have made a substitute fossil fuel. The idea is that car manufacturers, consumers and fuel retailers wouldn’t even notice the difference - it would just become another part of the fuel production chain.”

“What we’’ve done is produced fuels that are exactly the chain length required for the modern engine and exactly the composition that is required. They are bio-fossil-fuels if you like.”

However, the E. coli did not make much of the fuel. Professor Love said it would take about 100 litres of bacteria to produce a single teaspoon of the fuel.

“Our challenge is to increase the yield before we can go into any form of industrial production,” he said.