British Airways has confirmed that cracks have been discovered in the wings of all seven of its Concorde supersonic jets.

One aircraft has been taken out of service after a crack was found to have lengthened. But the airline says the rest of the fleet remains safe to fly.

The 60mm long microscopic cracks were found using ultrasonic testing equipment.

They have occurred in the rear wing spar - a beam that makes up part of the aircraft structure - of each of the Concorde fleet.

'No safety risk'

British Airways says it has reported the discovery to the French manufacturer, Aero Spatiale, and to the Civil Aviation Authority, which agreed that the aircraft remained safe to fly.

The cracks are said to be in a non-safety critical part of the plane. However, last week a crack on one aircraft was found to have grown to 76mm, forcing BA to ground it.

That Concorde has now been taken out of service while a new part is made and fitted - a job that will take two months.

A BA spokeswoman said: "They have all been checked by the CAA which is happy for them to fly and there is absolutely no risk to the public in the six other aircraft. We are hoping the one will be back in service by September.

"It's not a safety issue. We wouldn't fly if there was any risk to safety,"

BA says it will continue to monitor the cracks on the other aircraft and it says safety will not be put at risk.

The supersonic aeroplanes can carry 100 passengers and fly at 1,336mph and at an altitude of 55,000 feet.