Prince Charles will tour the country in a chip fat-fuelled train this week, and be raced to London on the last leg by two West design gurus driving two electric supercars.

The prince has created Start to demonstrate what a more energy efficient, cleaner and healthier future could look like.

He asked Roger Saul, creator of fashion brand Mulberry, spelt organic food brand Sharpham Park, and television presenter Kevin McCloud, to help change the way people think about cars, travel and the environment.

The Somerset-based friends who share a love of speed, organised an eco car challenge which culminates in a sustainability extravaganza in The Mall this Sunday.

It will see a series of parades of the latest eco cars, motorbikes, scooters, and other transport, with celebrity drivers including motoring legend Sir Stirling Moss, Dame Ellen MacArthur, Dragons' Den's Duncan Bannatyne, Sanjeev Bhaskar, Boycie, and Gabi Roslin.

A Tag Heuer Tesla electric car which has been driving around the world will complete its journey during the day. It is hoped Dragons' Den judge James Caan will be at the wheel.

Jools Holland has created music for the spectacular, which is expected to draw a crowd of more than 50,000.

Mr Saul and Mr McCloud began their challenge in Somerset earlier this year when they trialed a Californian electric Tesla Roadster super car and a Norwegian THINK Electric Car.

After the trials Mr Saul said: "What impressed me most about the two eco cars was just how far battery technology has come.

"There is no doubt it will be the next step in the automotive power train."

The friends will race the train from Birmingham on Thursday, driving two Tesla supercars to demonstrate style, speed and carbon footprint.

The spectacular will raise funds for the Prince's charities and Bottletop.