McDonald's is to convert all its UK delivery vehicles to run on biodiesel, using the firm's supply of cooking oil.
The firm says it is determined to reduce its carbon footprint
The fast-food chain has pledged to convert all its 155 vehicles by next year, starting with 45 lorries based at its distribution centre in Hampshire.
By using the fuel - made by combining cooking oil and rapeseed oil - the firm said it would save more than 1,650 tonnes of carbon every year.
The move follows a successful trial last year.
McDonald's has long faced criticism over its environmental record.
The firm said it was "delighted" to be putting its large stock of cooking oil to a "practical, efficient use" within its own business.
"This is a great example of how businesses can work together to help the environment," said its senior vice president Matthew Howe.
The retailer added that it was working on a range of other initiatives spanning recycling and packaging to reduce its carbon emissions.
It said it was committed to working with its suppliers to reduce the use of pure rapeseed oil in its manufacturing process.