A green flywheel first developed for Formula One cars will be retro-fitted to buses in Putney.

Six buses will boast the flywheel, which produces electro mechanical energy to drive the bus and reduce carbon dioxide (CO2) emissions.

The devices were originally developed for Formula One cars by William Hybrid Power (WHP), but were abandoned due to a regulation change by the sport's administrators.

WHP are now making the technology available on hybrid buses to help save fuel and reduce emissions.

Go-Ahead buses, one of the UK's largest bus operators will make use of the technology, with predictions it could reduce fuel use by about 30 per cent.

Phil Margrave, group engineering director, said: "In the ongoing quest to significantly reduce the CO2 emissions of the Go-Ahead Group we are very excited to be working with Williams Hybrid Power, a British technology company at the cutting edge of alternative energy solutions.

"We are convinced that the experience and expertise they have gained from developing and using the flywheel technology in motorsport will migrate to the bus market and deliver a ground-breaking solution to the issue of fuel efficiency."

Ian Foley, managing director of Williams Hybrid Power said: "From the very beginning we identified public transport as an ideal customer for our flywheel technology and I am excited about meeting the challenge of delivering this innovative solution for the bus industry."