A British Airways captain sank the equivalent of ten pints of beer before work and slept through a flight to London, it was alleged today.

The pilot reported for duty for the flight from Barcelona after only two hours' sleep following a heavy late-night drinking session with fellow crew members, a TV documentary claimed.

The Channel 4 Dispatches programme - shown to the media today ahead of next Thursday's screening - reveals what its maker claims is the "endemic" culture of drinking among BA flight crews.

Of the 12 pilots filmed for the hour-long programmes, ten broke BA's regulations on drinking before reporting for duty.

BA has suspended 11 pilots and three cabin crew staff on Gatwick routes over the allegations.

Deputy Prime Minister John Prescott said: "I am concerned about anything which affects aviation safety. If there is anything in these allegations I shall want the safety regulators to act.

"But I am also concerned that a television company appears to have had this information for some time but has only now made it public.

"If the company has further information in relation to this case they should make it available immediately to the Civil Aviation Authority, which can investigate the allegations."

Unions representing the accused aircrew challenged Channel 4 to prove its claims. The Amalgamated Engineering and Electrical Union said it wanted the names of the workers under investigation following claims the station had used underhand methods to entrap them.

But Channel 4 spokeswoman Melinda McDougall said: "We have evidence of BA pilots drinking to excess and then reporting for duty in breach of the eight-hour ban on alcohol."

BA crew members are not allowed to drink alcohol in the eight hours before reporting for flight duty and must only drink in moderation during the 24 hours before a flight.

Ms McDougall said: "We stand by our report and strongly deny any accusations of entrapment."

The British Airline Pilots' Association attacked the programme for "its underhand and disgraceful journalistic methods".

BA, meanwhile, said the accused staff had been removed from duty pending an internal investigation.

All of those suspended work on short-haul routes, mainly out of Gatwick. They include at least one stewardess.