BP wants motorists to pay £20 a year to reduce their impact on the environment from using petrol in their cars.

Drivers will be able to calculate their annual carbon emissions on the oil company’s website and then pay to have them ‘offset’ in a new scheme called targetneutral.

BP says an average car, driven 10,000 miles a year, generates around four tonnes of CO2. This would cost around £20 to neutralise, typically achieved through funding wind farms or solar energy plants that cuts a similar quantity of emissions in a developing country.

BP will make no money from the scheme. Everytime a driver pays, BP will contribute an extra sum of 10p per tank of ordinary fuels and 20p per tank of its Ultimate fuels. Five projects will be financed through the BP website, www.targetneutral.com, including a system to capture and use methane from animal waste in Mexico.

Carmakers have already introduced offsetting schemes. Honda has offered to offset driver emissions while they are waiting for delivery of a Civic Hybrid and from next year Land Rover customers will be asked to pay extra to offset three years of emissions from their vehicles.