Sir Clive again hopes his invention will revolutionise travel in cities

He has launched what he calls "the world's smallest, lightest, foldable bicycle" - the city-dwellers' A-Bike.

The bike, which will cost around �170, weighs only 12lbs but is built to support riders weighing up to 17 stone.

It is to go on sale in Singapore shortly, followed by the UK, the US and Japan next year.

Zipped into a bag, the A-Bike resembles a large umbrella when folded - taking up 0.03 cubic metres - and can be stored away under a desk.

Segway scooter

Sir Clive said: "My original thought was that if you could have a bicycle that was dramatically lighter and more compact than ones that exist today, you would change the way in which bicycles could be used."

Like the US-made Segway scooter, the aim was to find ways of gliding through congested cities. It is also aimed at yachtsmen and campers.

Sir Clive, who also invented the one of world's smallest calculators in 1972 and the pocket television in 1984, promises: "You need no extra energy to ride the A-bike and it can go up to 15mph."

The bike has been designed and built in a collaboration between Northamptonshire-based Sinclair Research Ltd and Hong Kong's Daka Designs.