The electric motor-powered chemical loo will travel 874 miles from Land's End to John O'Groats, at the tip of Scotland.

Driver Hank Harp, perched in his driving position on the toilet seat, set off from Cornwall with his en-route refreshment stored safely in the bowl.

Refreshments are stored in the toilet bowl

The trek is the brainchild of Steve Gilks, from Wakefield, West Yorkshire, who made the same trip in a motorised shopping trolley in 1989.

Mr Gilks, who runs Cash for Trash which converts household rubbish into cash for charity, hopes to raise �10,000 for hospices.

The motorised toilet was built by British Aerospace trainees Andrew Threlfall and Lyndon Poskitt at Brough, East Yorkshire, as part of their Duke of Edinburgh Gold award scheme. It is powered by a 24-volt motor, and tows a wheelie-bin to collect rubbish for recycling.

The vehicle will have to keep out of the fast lane...

Tank Regiment Sergeant Harp, from Crewkerne, Somerset, took the driver's job after the original driver was unable to make the trip.

Mr Gilks, who suffers from asthma, angina and bone marrow problems, will be presenting equipment to hospices and GPs along the route to help patients with breathing problems.

The length-of-Britain trip has attracted many modes of transport in the past, including people on horseback, roller skates, a unicycle, tractor and mechanical digger. They have raised millions of pounds for charity.