Bridgestone Motorsport has announced that it will leave F1 at the end of the 2010 world championship campaign, becoming the third major manufacturer to walk away from the grid in the space of two years - though it insisted the global credit crunch was not the root cause.

Bridgestone entered F1 back in 1997 as a rival to Goodyear, and has been the sport's sole tyre-supplier since 2007 - a year earlier than scheduled - following Michelin's premature withdrawal in the wake of the Indianapolis d?b?cle. Its current contract expires at the end of next year, but only a day after the season-ending Abu Dhabi Grand Prix, the Tokyo-based company has revealed that there will be no renewal, casting uncertainty over just who will next pick up the mantle - with Michelin thought distinctly unlikely to return.

'Bridgestone today announced that it will not enter into a new tyre supply contract with the FIA Formula One World Championship,' read an official statement, explaining that it was 'addressing the impact of the continuing evolution of the business environment'.

'The decision made by the board of directors of Bridgestone comes after considerable and lengthy evaluations, and has been based on the company's need to redirect its resources towards the further intensive development of innovative technologies and strategic products. While we understand and respect the reasons for this decision, it has nevertheless come as a great disappointment.

'Bridgestone's relationship with the FIA Formula One World Championship stretches beyond being a tyre-supplier. F1 has been of strategic importance to Bridgestone in developing its technologies and the recognition of Bridgestone as a leader in the global tyre industry, raising the company's brand awareness and providing its strategic business units around the globe with promotional and marketing tools that are intrinsically linked to our company's core products.

'In 1996, Bridgestone's brand recognition in Europe's five largest countries was 13 per cent, but by 2003 it had risen to 34 per cent. In recent years the arrival of Bahrain and China to the F1 championship has enabled Bridgestone to increase its activity in the Middle East and Far East. Having achieved these goals, Bridgestone is now poised to take its technological and brand-building efforts to the next level.

'Our sincere appreciation is also extended to Mr. Bernie Ecclestone and Formula One Management, the Formula 1 teams with whom it has been an honour to have worked alongside, and the many Formula 1 fans who have followed our activities over the past 13 years. I would also like to thank the staff of the Bridgestone Motorsport team for their professionalism, dedication and hard work, and for their passion for excellence.

'It remains only to re-iterate that Bridgestone continues to be wholly committed to the provision of safe tyres of the highest quality to the FIA Formula One World Championship in 2010, and to the running of its tyre-servicing operation at the highest level.'

According to The Associated Press, Bridgestone - one of the world's two largest tyre-makers, along with Michelin - revealed a net loss of 38.34 billion yen ($420 million) for the first half of 2009, contrasting starkly with the profit of 37.24 billion yen in the same period of 2008. The net profit for the current financial year to March 2010 is expected to plummet by 42 percent year-on-year to six billion yen ($66.7 million). Last month it was announced that 900 jobs would go at plants in Australia and New Zealand, as the automotive recession increasingly takes its toll worldwide.

The international economic downturn, indeed, has claimed a number of high-profile F1 casualties, with Honda being the first to pull the plug on what is now Brawn GP last December, BMW following suit in selling off the former Sauber operation and doubts over the ongoing participation of Renault F1 and Toyota, which elected not to continue hosting the Japanese Grand Prix at the Fuji Motor Speedway that it owns.

Other Japanese companies have also been in the wars of late, with Subaru and Suzuki ending their official participation in the World Rally Championship last year, Kawasaki quitting MotoGP and Mitsubishi ending its support of the Dakar Rally.

Bridgestone has explained that one of its new priorities will be the development of more environmentally-friendly products and strategic technologies - and the company has insisted that it will endeavour to re-assign as many of its staff as possible at its headquarters in Kodaira to the west of Tokyo, with no decision yet made on possible job losses.

"The business environment is changing greatly," company spokesman Makoto Shiomi told AFP, dismissing speculation that the credit crunch had played a significant role in the decision. "We need to concentrate our management resources on strategic areas and technological innovation."

"The company has decided to redistribute its resources as part of a changing business strategy," added public relations manager Kaoru Tomizawa, speaking to Reuters. "There has been a change of direction towards further developing areas of the business where demand is greatest and which support the company's aims. It is not mainly the depressed economic situation; we are looking more at where tyre demand needs to be focused.

"We still have a year left in F1, so no final decision has been taken on how it will impact the employees - but we would like to respect their contribution before deciding about that."