Updated

Using biofuel in vehicles could accelerate the destruction of rain forests and result in higher greenhouse gas emissions than burning pure gas and diesel, The Times of London reported Friday.

The U.K.'s Renewable Fuels Agency (RFA) warned Thursday that gas prices could rise in April because of the government’s policy of requiring fuel companies to add biofuel to gas and diesel. More than 3.2 million acres of land were used to grow the 2.7 percent of Britain's transport fuel that came from crops last year.

Under the British government's Renewable Transport Fuels Obligation, a growing proportion of biofuel must be added to diesel and gas. This year, fuel must be at least 3.25 percent biofuel on average. By 2020 the proportion was set to be 13 percent.

The RFA's first annual report said fuel companies exploited a loophole to avoid reporting the origin of almost half the biofuel they supplied to filling stations last year. Last year Esso reported the source of only six percent of its biofuel and BP reported 27 percent. Shell was the best-performing of the main oil companies but still failed to report the origin of a third of its biofuel.

The origin of fuel from land recently cleared can be described as "unknown."

“The large proportion of unknown previous land use is of concern," the RFA said.

"If even a small proportion of this was carbon-rich grassland or forestland, it could have substantially reduced the carbon savings resulting from the renewable transport fuels obligation as a whole, or even resulted in a net release of carbon."

Most companies met part of their biofuel obligation by buying palm oil, one of the cheapest fuels but potentially the most damaging to the environment because of the carbon released when forests were burned down to create plantations.

Read more at The Times of London.