With the glut of Christmas consumption already in full swing, it seems fitting that a bus which runs on waste fats and oils should also be getting into gear.

Almost a third of the capital’s bus fleet are to run on a greener blend of diesel by March, after Route 69 from Walthamstow to Canning Town trialled the least wasteful ride of its kind.

Cleaner burning fuel biodiesel is being phased in by bus operators Stagecoach and Metroline. The product, B20, is made from blending diesel with renewable biodiesel from waste products, including cooking oil and tallow from the meat processing trade.

The move should cut CO2 emissions from each bus by more than 10 per cent, slashing a total of 21,000 tonnes a year.

“Our bus fleet is now making a major contribution to improving air quality and bringing down CO2 emissions,” commented Mike Weston, Transport for London’s director of buses.

“This improvement, which will reduce CO2 emissions by 21,000 tonnes each year, is being introduced now with no extra spend needed and no long delay for the fitting of new kit. It’s just one of a number of measures we are taking to make London’s environment better for everyone.”

By March, almost 3,000 of the capital’s 8,900 buses will be powered by the B20 fuel blend. Six hundred and forty-two buses operating out of four Stagecoach depots have already been using B20 for two months on a trial basis, after the initial route on Route 69.

Deputy mayor for environment and energy, Matthew Pencharz, added: “As a leading global city London has an important role to play in reducing greenhouse gases and minimising our contribution to climate change.

“This is ongoing progress for running our bus fleets on waste products and cutting CO2. We will continue to work with our industry partners to use more of London’s used cooking oil turned into biodiesel right here in the city, creating green jobs and fuel self-sufficiency benefits.”