The British Airline Pilots Association (Balpa) revealed the shocking statistics to highlight fears about an increase to the number of hours that pilots work, proposed by the European Aviation Safety Agency.

The proposals would increase the number of hours a pilot can spend at work from 16 hours 15 minutes a day to 20 hours.

Balpa said that 43 per cent of the 500 members who responded to a union survey confessed they had fallen asleep on the flight deck.

Rob Hunter, the union’s head of safety, told the Transport Select Committee that pilots feared disciplinary action if they complained of being tired.

“It becomes a better option to put up with a bit of fatigue rather then report it,” Hunter said.

If the European proposals go through, considering the time pilots spend getting to work at the start of a shift, it could mean they are at the controls of an aircraft as much as 22 hours after they got up.

But “22 hours of wakefulness is far from the only part of the proposals which give us serious concern,” said Jim McAuslan, the union’s general secretary.

“Compared to the UK’s domestic rules, the EU proposals would see pilots being able to fly further – as far as California – with no backup crew and, contrary to scientific advice, allow pilots to do up to seven early starts in a row, which is desperately fatiguing.”

But the Civil Aviation Authority backed the proposed changes. “Overall we now think the current proposal, together with other regulations, such as the European Work Time Directive, and our continuous oversight of airlines, provides a package that will work for Europe,” a spokesman said.