In the cutthroat battle for business-class airline passengers, any competitive advantage is jealously guarded - even the shape of the seats.

Virgin Atlantic is understood to have started legal proceedings to protect the design of its Upper Class product after competitors started to roll out suspiciously similar seats. Industry sources said that Sir Richard Branson’s airline was suing Contour, a Wales-based seat manufacturer, for breach of patents.

Virgin spent £50 million developing the herringbone shape and layout for its Upper Class and introduced it with great fanfare in 2003. Airlines sell business-class tickets, which generate most of their profits, on features such as the flattest bed and best in-flight entertainment. The largest airlines develop their own seats in order to have a unique sales proposition. Virgin has two patents covering the shape and configuration of the seats and the technology used to lower the seat into a bed.

Contour built Virgin’s seats, but the company has also supplied herring-bone-shaped seats to Delta, Cathay Pacific, Air Canada and Jet Air.

Virgin is thought to be seeking damages from Contour and is also thought to be demanding that these other airlines remove their seats, which could cost them millions of dollars in lost revenue. Contour declined to comment and a spokesman for Virgin Atlantic said that the airline did not talk about active legal proceedings.

Delta, Cathay Pacific and Air Canada are in the process of installing the new seats. Jet, an Indian airline, has already fitted out its aircraft.

Contour was founded in 1933 as LA Rumbold to supply seats for DeHavilland aircraft. The company has also made seats for BOAC, British Airways and British Caledonian. It is a subsidiary of the Premium Aircraft Interiors Group, which in turn is a subsidiary of the Seton House Group, an engineering business. Seton House, which is 81 per cent owned by Royal Bank Equity Finance, reported sales of £459 million in 2005, of which £263 million came from aircraft interiors.

Virgin has always sought to differentiate itself from larger competitors by developing innovative service ideas. Upper Class passengers have a bar area onboard and can get massages at their seat. Ticket prices for an Upper Class seat from London to New York are about £4,000 return and the airline is jealously protective of this market. It has licensed the herringbone design to only one other airline, Air New Zealand.

Last week, Singapore Airlines introduced onboard cabins for first-class passengers. It received its first A380 superjumbo from Airbus last Monday and has equipped the double-decker aircraft with 12 individual cabins.

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