Pilots' leaders warn today of cancelled flights this summer leading to airport chaos because of controversial plans to extend flying hours.

The British Airline Pilots Association (BALPA), and 14 other organisations representing pilots across Europe, have warned that the likelihood of air crashes will increase six-fold if duty hours are lengthened.

They say pilots may not stick to the new limits if they believe they jeopardise passengers' lives - raising the prospect of grounded planes and passenger delays.

And while some airlines say they believe the EU proposals would not affect their pilots' hours, BALPA say they will be encouraged to change because of the competitive pressures faced by the industry.

BALPA general secretary Jim McAuslan said: "Under the European proposals it will be possible for an airline to tell two pilots to fly from London to Sydney with a brief stopover in Bangkok or Singapore instead of what we have now, a flight crew of four.

"Experience tells us that this will be a disaster."

Under the controversial plans, the EU is proposing to increase maximum flight duty hours for pilots from the current 12 to 14 at a stretch.

Rest time between flights would be cut and there would be no limit to the number of consecutive night flights a pilot would be required to fly, according to BALPA.

The unions will present their findings on Thursday to a meeting in Luxembourg of the European Union's Council of Transport Ministers who are due to decide on duty hours.