THE sleek de Havilland Comet, the world’s first commercial passenger jet, was designed and built in Britain 60 years ago. It is a dozen years since the last passenger jet, a small regional airliner, was assembled in the country. This would neatly illustrate a familiar tale of industrial tailspin were the industry not in such fine fettle. Britain is currently the world’s second-largest aerospace manufacturer, with 17% of the global market, behind only America. But staying at that altitude will be tough.

Britain’s aerospace industry has a few obvious champions: Rolls-Royce makes engines, BAE Systems makes fighter jets and AgustaWestland turns out helicopters. But much of it is hidden and unheralded. Its muscle is in unlikely places like Western Approach, an anonymous industrial estate near Bristol, where GKN crafts wing spars for Airbus. The long, slender beams that carry engines, landing gear and wing structure are made from light but tough carbon-fibre composites. GKN got the job because of its mastery of the material and its ability to produce in volume. GKN also makes parts for Airbus’s arch-rival, Boeing.

Rolls-Royce’s engines now provide the thrust for half the world’s new wide-bodied jets. Around a quarter of Boeing’s 787 Dreamliner is made in Britain, including the landing gear, fuel pumps and some seats. British firms are world-beaters in avionics, the electronics that run a modern jet.

In short, Britain specialises in the complex guts of aeroplanes. Airbus completes construction of its wings in Wales before transporting them to southern France for attaching to fuselages. Bombardier, a Canadian firm, builds the wings for its new CSeries of regional jets in Belfast. Politicians in other countries crow as completed planes roll off production lines on home turf. French participation in the Airbus consortium was contingent on jets being put together there. But the British are quietly coining it: a measly 5% of the value of an aeroplane is added with final assembly.

Rising global demand for commercial jets means business will boom if Britain maintains its share of the market. Unfortunately, this is far from guaranteed. Companies are under-investing in research just as changes in the industry make it more vital.

Aerospace is a conservative business, says Glynn Bellamy of KPMG. Projects often have lifespans of 25-30 years, and reliability is paramount. As a result the industry has globalised only slowly and Western incumbents have been insulated from the cold winds of competition. But several things are changing that.

Some big commercial airline projects, such as the Airbus A330 and the original Boeing 777, are coming to an end, to be replaced by a new generation of narrow- and wide-bodied jets. That provides an opportunity for the big global manufacturers to look beyond their backyards for suppliers. Meanwhile the governments of emerging economies like China and India are eager to boost a high-tech, high-value industry.

Technology is advancing and becoming far more costly. Andrew Churchill, who runs JJChurchill, a family firm that makes turbine blades and other high-tech kit, says capital equipment is ten times more expensive it was a decade ago. It also becomes obsolete more quickly.

The solution to all these problems is the same: plentiful research and development to keep British companies at the cutting edge. At the biggest companies, long-term investment is taken for granted. Rolls is already developing next-generation jet-engine technology. JJChurchill has ambitious plans to expand. But Mr Churchill says other small firms are failing to raise their game. If that continues, the industry will decline.

Britain is home to 30% of Europe’s aerospace firms, according to Martin Wright of the Northwest Aerospace Alliance, a trade organisation. Germany has only 10% but they are over twice as big on average and invest twice as heavily.

Britain’s government has done a good job of nurturing aerospace, says Keith Hayward of the Royal Aeronautical Society. It has set aside cash for an Aerospace Technology Insitute and for large and small firms to invest in new technologies. ADS, an aerospace lobby group, would like to see R&D tax credits increased from 10% to compare more favourably with other parts of Europe, as well as accelerated tax relief on new building to help smaller firms move and grow.

That would help. But convincing small firms to grow is a tough task. The government can only do so much to reduce the powerful gravitational forces acting on a fragmented national industry. Like the Comet, nothing stays airborne forever.