Hovertrain at Sutton Gault and Eric Laithwaite

There now follows a scientific explanation. Those of you who fear you may lose the will to live while reading this section can skip the next three paragraphs.

An electric motor, such as the starter motor in a car, comprises sets of multiple loops of thin copper wire placed around a central iron rotor. When an electrical current passes through one of the sets of loops it creates a magnetic effect that attracts the rotor and makes it move round. This also moves a connection so that the current then passes through the next set of loops. Its magnetic effect attracts the rotor and moves it further round. The connection moves on to each set of loops in turn and so the rotor is pulled round.

A linear induction motor is the sets of wire loops of an electric motor laid out in a line. As the electric current passes through each of the loops in turn, it sets up a magnetic effect rippling along a metal track. This pulls the loops, and the vehicle in which they are set, along the track. It has been described as a magnetic river with the vehicle moving along in its flow.

Early versions of the hovertrain rested on a cushion of air, like a hovercraft that travels over sea or land, but later ones could levitate. No, it wasn't yogic meditation by the driver, just good old magnetism again. Like poles repel, as we all remember from pushing magnets around in the school lesson. So if you make the magnets strong enough and align them correctly, they can lift the train off the track.

And there you have a Maglev - a magnetic powered, levitating train. This method of transportation is very efficient. Because of the levitation, there is no friction from sliding along the track. There are no metal wheels to slip on rails. The absence of moving parts in the motor and no wheel contact also means that there is hardly any noise or vibration.

The British government of the time was interested in new forms of high speed mass transport and pumped £35m into the development of the hovertrain. The Sutton prototype reached speeds of 100 mph but the project was cancelled before it was fully developed

Other countries have continued this exciting work. The Japanese have spent a £1billion and are now fine-tuning the Chou Shinkansen experimental train that has achieved speeds of 350mph (560 kph). Germany's Transrapid consortium are building a Maglev between Shanghai's international airport and the city centre that will do the 35 km journey in seven minutes. It is due to open in 2004 and will be the world's first commercial high speed hovertrain. Britain's efforts have been embarrassingly mundane. There was a shuttle that ran on a 600 metre track between Birmingham International Airport and a nearby railway station at steady trot of 26mph (42 kph). It operated from 1984 to 1995 but had several problems and was eventually shut down and replaced by a bus.

The track at Sutton has been dismantled but some traces remain. The experimental train, romantically named the RTV31, is one of the outdoor exhibits at the Railworld Museum in Peterborough, a short drive away. The museum also has one of the Birmingham Airport shuttle vehicles.

The hovertrain was the brainchild of Eric Laithwaite. Born in 1921 in Atherton, Lancashire, he had a grammar school education, went on to Manchester University, served with the RAF during the war developing automatic pilot systems, returned to Manchester University as a lecturer and, in 1964, became Professor of Heavy Engineering at Imperial College, London.

In 1948 he took out a patent for a linear motor to drive a shuttle across a loom. By 1962 he was working on this method of propulsion for trains as a consultant to British Railways but, disillusioned by their lack of investment, transferred to their rivals, Tracked Hovercraft in 1967 and got the contract from the government to do the work on the Sutton hovertain.

The cancellation of the project was a severe disappointment to Prof Laithwaite but it did not dampen his broad enthusiasm for scientific enquiry. His knack for explaining ideas had made him a popular figure on radio and TV. He wrote books for the general public, including "Exciting Electrical Machines" and "How to Invent". He was a keen entomologist, with one of the finest British collections, and co-authored "The Dictionary of Butterflies and Moths". Reciting poetry from memory and telling anecdotes from his formidable collection were non-scientific pleasures.

As a media scientist he was subject to the intrusions of many amateur inventors. Unlike most of his colleagues, who simply binned communications from such "cranks", he was always curious and open minded. One letter, in particular drew his attention. The inventor, Alex Jones, claimed to have made a devise that moved without any power drive to its wheels or jet thrust. Prof Laithwaite invited Jones to his laboratory and was shown a model powered by a gyroscope that did indeed seem to move of its own accord.

Laithwaite could not explain why this happened and so started to investigate gyroscopes out of sheer curiosity "like Alice following the White Rabbit" as he was later to recall. He gradually became convinced that they did break the laws of motion and could be a hitherto unrecognised source of power.

When he was invited to give the 1974 Faraday Lecture at the Royal Institution, Prof Laithwaite thought that his investigations would be a suitable topic. Being a bit of a showman, he took along a number of examples, including a huge 50lb gyroscope that, when he spun it, he was able to effortlessly raise above his head with one hand. "Look. It's lost weight" he exclaimed to his audience.

He had offered no explanation of why the gyroscope seemed to be lighter and indeed had none. He was simply presenting the evidence and asking "Why?" The scientific world were more concerned about this heresy against the Laws of Isaac Newton (one of their Gods), than they were in taking up the intellectual challenge of answering the question. Laithwaite was supposed to supply proven answers, not create uncertainty.

Criticism, possibly tinged with envy of his media fame, was bitter. The reaction even went so far as the Royal Institution not publishing his Faraday Lecture. His nomination to the Fellowship of the Royal Society was cancelled. The Royal Society later denied this, saying that his candidature lapsed because he was not elected within seven years of nomination.

Although his work was regarded as cranky and lacking rigour, he never gave up the investigation of gyroscopes, even after he retired in 1986. In 1993 he applied for a patent on a gyroscopic space drive with, typically, a demonstration model that he had built with his childhood Meccano set.

He also had the last laugh on his critics, although through his induction motors rather than his gyroscopes. NASA engaged him to help build a rocket launching system using magnetic motors. The plan is to build a three mile (5 km) track in an inclined tunnel driven through a 10,000 ft mountain and use magnetic motors to accelerate a 20 tonne spacecraft to 600 mph (960 kph). The rocket engines will then cut in and take it into orbit. This will save millions of pounds by replacing the first stage rocket that accounts for two thirds of the cost of a launch.

Small scale trials have started. A model reached 60 mph (96 kph) on a track that was only 50 ft (16 m) long and a 200ft (60m) track is being prepared that is expected to produce speeds of 200 mph (320 kph). Eric Laithwaite was happily working on this project when he collapsed and died at the age of 76. Probably the way he would have wanted to go, although I can imagine him complaining at the Pearly Gates that God had cancelled his project just when he was getting somewhere.