Terminal 5 is a "distressing shambles" that is an "acute embarrassment" to the UK, British Airways pilots say.

In an open letter to the Government and city investors, the British Airline Pilots' Association says "BA management has taken its eye off the ball" and is putting the company at risk.

Association general secretary Jim McAuslan said it was time for BA chief Willie Walsh to step down.

BA pilots are embroiled in an industrial dispute over the airline's plans to use non-BA pilots on in its new subsidiary OpenSkies.

"It is with great sorrow and acute embarrassment that BA pilots have witnessed the unhappy, distressing shambles that the opening of Terminal 5 has become," Mr McAuslan says in the letter.

"BA pilots have reacted in the right way by once again going the extra mile to solve problems and extend their working duties to maximum legal limits in order to minimize the suffering of our customers and protect the company they love and the uniform they wear.

"There is something very wrong right at the heart of this company that is making our once great brand a laughing stock.

"The ramifications of what is going on in BA will be felt far more widely.

"Our reputation as a country has been harmed no end. When you are running a national icon you have responsibility for far more stakeholders than shareholders."

A BA spokesman said Mr Walsh had repeated his determination not to quit.