The Liberal Democrat spokesman for defence said the internal survey uncovered more than 1,000 incidents of harassment in the past 12 months.

Mr Keetch, MP for Hereford, said the figures raise serious questions about the level of bullying in the service.

The RAF said it did not condone any form of harassment.

'Vulnerable members'

The report is based on a survey of 2,500 RAF personnel of all ranks.

It found victims were typically harassed by two or more male servicemen of a senior rank.

Most of the women were said to have been groped or subjected to sexually explicit remarks or gestures, although only half of them made a complaint.

Mr Keetch is now calling on the RAF to institute an urgent reform of the complaints system which he says is profoundly inadequate.

He said: "By and large the people that serve in our armed forces are excellent - magnificent men and women.

"But there is undoubtedly a small number of people who are preying on the vulnerable members, whether they be trainee soldiers or women in the Royal Air Force."

'Chain of command'

He added: "We have to make sure that this element is taken out of our armed forces so that they remain one of the finest, best disciplined forces in the world."

A Ministry of Defence spokesman said the survey was prompted by a desire to address such issues.

He said: "The services do not condone any sexual harassment or any bullying.

"This particular survey is one of this that is undertaken by the forces in order that the chain of command can get a snapshot about what the forces themselves are thinking about certain issues.

"That helps us to develop policies to get rid of this sort of behaviour."