An airline said it has found no evidence that one of its stewardesses screamed that everyone was going to die when a jumbo jet encountered severe turbulence.

Passengers claimed the Virgin Atlantic stewardess screamed every time the Gatwick to Las Vegas Boeing 747 dropped.

At one point she was said to have chanted three times: "We're going to crash" and also allegedly said everybody was going to die.

Virgin yesterday said it had completed its investigation into the flight of February 24 this year, saying that the turbulence three hours into the flight was the worst in the airline's 22-year history.

It said: "Evidence from passengers clearly states that, due to the severe nature of the turbulence, there was much noise and commotion onboard and several passengers were heard screaming during the incident.

"In particular, the findings of the investigation have concluded that, based on the evidence put forward by the passengers and crew questioned, the allegations against the individual crew member cannot be substantiated."

Sir Richard Branson, the airline's chairman, said: "The turbulence on this flight was unexpected and severe and Virgin Atlantic apologises to passengers for any distress it may have caused."