Boeing admitted yesterday that the 787 Dreamliner will be delayed by a further six months as it struggles to assemble the revolutionary new aircraft.

The 787 is the largest industrial project in the world with orders worth more than $120 billion (£59 billion).

The delay is likely to cost Boeing heavy compensation payments to customers.

Boeing said first deliveries of the aircraft will now be in late November or December 2008 rather than May.

Boeing shares fell nearly 3 per cent to $98.43 in afternoon trading in New York.

The news will come as a blow to All Nippon Airways, which was due to receive the first aircraft.

The Japanese carrier was hoping to have the 787 in its fleet in time for the Beijing Olympics, which would have given it maximum exposure and bragging rights.

Last month, Boeing said it was delaying the first flight of the 787 until some time between mid-November and mid-December.

The first-flight target had already slipped from the end of August to September and will not now take place until May next year.

When the first-flight delay was revealed last month, aviation analysts were sceptical that Boeing would be able to stick to its original delivery date as it squeezed the regulatory certification period down to just six months.

More production delays have now forced the company to reschedule not only the aircraft’s first flight but also deliveries.

However, the tight certification period remains and analysts said yesterday that further delays were still possible if any problems emerged when flying the aircraft.

The effects of the delay will be felt by dozens of airlines, possibly including British Airways, which has announced it is buying 24 787s.

BA expected to start receiving the aircraft in 2010, but may have to wait until 2011. If there are more delays, BA may even struggle to receive its aircraft before the London Olympics in 2012, which would be a blow to the airline’s marketing and operational plans.

The 787 announcement comes just a week before Airbus finally delivers the first of its A380 superjumbos.

Airbus, the European aircraft manufacturer, has barely recovered from a two-year delay to the A380 programme, which cost it billions of euros in compensation and billions more in lost earnings.

One analyst said: “The 787 delay is possibly the best thing that has happened to Airbus all year. It’s a reminder that these things never go according to plan.”

The 787 is being assembled in Seattle with carbon-fibre fuselage sections imported from all over the world fastened together using special clips. The untested construction method has proved problematic, not least because of a lack of fasteners.

Rumours in the aerospace industry suggest that Boeing may simply scrap the botched first plane and apply the lessons learnt to the second, hopefully completing assembly much faster.

Jim McNerney, chief executive of Boeing, said: “We are disappointed over the schedule changes that we are announcing. We remain confident in the design of the 787, and in the fundamental innovation and technologies that underpin it.”

The 787 is a mid-sized plane that will become a mainstay of the global long-haul fleet. Its lightweight carbon-fibre fuselage will allow it to cut fuel consumption, reducing airline costs and also carbon dioxide emissions.

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