An airport worker sexually harassed a female colleague before locking her in a cold store and threatening to kill her.

The incident is one of many reported since the an anti-bullying hotline was set up for staff at Gatwick.

Private sector union Amicus has called for an immediate inquiry after uncovering what it describes as a culture of sexual and racial abuse at the airport.

Dozens of ground staff and cabin crew reported disturbing tales of torment but leading airlines and the British Airports Authority today insisted their anti-bullying policies were sound.

The most extreme report was from a young woman who said: "I was locked in a cold store for 15 minutes to teach me a lesson because I complained about him touching me inappropriately.

"I was then told, if I took the matter further, he would make sure I froze to death the next time."

The union had contracted bullying specialists the Andrea Adams Trust to run the helpline for two weeks in July.

Ninety-one per cent of callers were from ethnic minorities and many spoke of racist abuse.

There were also various reports of inappropriate touching, groping and sexist remarks.

One caller said: "I love my job but the people I work with make my life a misery with cruel remarks made about my colour and family background. Because of my finances, I need this work so I have to put up with it."

Amicus wants to raise the profile of bullying and harassment procedures and to provide training and development to managers and union representatives for dealing with bullying and harassment.

Gordon White, national secretary for civil aviation, said: "Bullying is a disaster for morale, attendance and productivity. We are calling upon employers to get their houses in order for the sake of their staff and their business.

"We will be writing to employers and we expect them to work with the union to boot the bullies out of the airport."

The union has received £1.8 million from the Department of Trade and Industry to work with employers to tackle workplace bullying.

British Airways (BA) employs approximately 5,000 staff at Gatwick, including ground staff, cabin crew, flight crew, engineering, cargo and office-based employees.

A BA spokeswoman said the airline was committed to stopping harassment in the work place.

She said: "British Airways takes the issues of bullying and harassment extremely seriously.

"We introduced a policy five years ago after consultation with our trade unions.

"Our policy is absolutely clear - we will not tolerate bullying or harassment in the workplace.

"We are committed to ensuring the workplace is free from harassment and bullying and we encourage anyone who thinks that they are or have experienced such behaviour to report incidents promptly for investigation and action.

"Anyone in breach of this policy would be subject to disciplinary action.

"We are currently in the process of talking to groups of staff across the airline and reminding them of our stringent policy.

"All managers at British Airways have an obligation to attend equal opportunities and diversity courses, which cover issues such as bullying and harassment as well as other unacceptable behaviours."

The spokeswoman said staff have access to a confidential helpline where they can discuss any problems with a trained professional.

A British Airports Authority spokeswoman said: "We do not have any major bullying issues - this helpline is about the whole airport community.

"We have got about 800 members in Amicus and we have reviewed our bullying and harassment policy with the unions a couple of months ago. They said what we have got in place is sound."