Science: Lifting the cover on a composite rival to metal: Tim Verney on a breakthrough that started at the filling station

Motorway crash barriers, manhole covers, even structural components in vehicles, could in future be made of composite materials instead of metal.

It follows the discovery of a new manufacturing method for combined glass fibre and resin products. Other applications being looked at include seats in railway carriages and fence posts.

At the heart of the new possibilities lies a machine that weaves the glass fibre strands in structurally optimal alignments before resin is injected to bond the whole arrangement together.

Despite the complex technology involved, the origins of the latest breakthrough are grounded in something far more mundane, a feature motorists regularly drive over at petrol filling station forecourts without a second thought - the covers in the ground which must be removed to allow access to the tanks for the pumps.

A decade ago, a survey showed that up to a third of fuel tanker drivers in one BP region of the country were off sick at any one time, the result of backstrain and hernias caused by painful struggles in trying to remove the heavy metal covers, weighing some 65 kilograms.

There had to be a lighter solution and a new tank cover, made of composite materials, provided the answer. At 30kg, it was less than half the weight of its metal predecessors, but was still able to withstand a punishing load test of 30 tons per square foot.

They are now in relatively common use at filling stations around the country. One cover supplier estimates they are present on about a quarter of forecourts.

But the latest advance came after researchers at Cambridge Consultants Ltd (CCL) were asked to refine the tank cover design further. This request arose because composite covers designed for the United States threatened to be less useful since, being larger than those in Britain, drivers still faced a job that was potentially almost as back-breaking even when the lighter material was used.

In the end CCL, in conjunction with the Yorkshire company Fibrelite Composites, which had produced the original cover, succeeded in pioneering a new form which will cut the weight of a 30kg cover by a further 5kg.

The significance is not just that new lighter covers will start to appear in our garage forecourts, but that the researchers will now be able to open up an enormous potential market for all manner of structural components made from composite materials, a market which at present is dominated by metal.

Eric Wilkinson, head of composites at CCL, described it as the most important development in composites research for 10 years and well worth the company's pounds 500,000 investment.

'It is rare for us to get involved in any development work that isn't funded by clients,' he said, 'but we were convinced that there was a major commercial opportunity here.

'It is not a market that is easy to create quickly, but it is certainly going to generate enough business to keep us happy over the next few years.'

Mr Wilkinson estimated the money-spinning capacity of the new machine at millions of pounds.

The task now, he said, was to identify potential markets. They fall in a range between the highest-grade composites, such as carbon fibre products used in the aerospace industry, and low-grade products satisfactory for boat hulls or crash helmets.

'The problem is that because of this polarisation from which composites suffer, people find it very difficult to imagine the potential market for this technology.

'They are thinking of extending existing applications, which are necessarily limited, rather than looking at the middle ground where composites so far haven't made an impact.'

The machine that CCL has adapted during the five-year project works like a loom. With the ideal position for fibres worked out using computer-aided technology, it is able to line up a pattern and then weave the glass yarn into large numbers of the required shapes, known as preforms. What is special about the preforming machine is that it can do the job automatically, at very high speed, and weave in three dimensions simultaneously.

CCL is reluctant to discuss the mechanism in detail. A protective patent has been taken out. Meanwhile, the company has set up a pilot manufacturing facility on which preforms for both manhole covers and railway seats have been made and is discussing new applications with companies in Europe.