Several serving and former female NHS paramedics have told Sky News how they were pressured for sexual favors by colleagues and bosses for promotion or to keep their jobs. The head of the NHS whistleblowers office has said it shows women aren't safe in the ambulance service. A warning that Rachel Bennerbles' story does contain reports that contain sexually explicit language and descriptions of sexual harassment.

A uniform which should make you feel safe. But three, former and current But this ambulance workers have told Sky News their years wearing it were marred by harassment, with women even pressured for sexual favors.

Say you make a mistake in protocol, you'll get someone say to you, Well, I'm going to report you if you don't have sex with me. I said to the guy, Well, report me. And he said, Well, just watch your back because I could rape you.

Former paramedic Katie remembers students being Particularly vulnerable.

There were lots of men out there who would want sexual favors to pass you or sign you off, maybe on your portfolio. This one guy, actually, I worked with him, and he did say to me, Let's go out. If we go out for drinks, I can get this signed off. He was predatory.

She says sexual favors were seen as a joke or part of the banter.

They were obsessed with blow jobs. Everything was about them. Give me one and then I'll do this.

For years, cultural reports have raised concerns about the number of women in the ambulance service being hounded for sexual favors by their colleagues or bosses. At the heart of the problem seems to be the huge power imbalances at play, but also a culture in which people just don't feel safe in speaking up. This is something the head of the NHS whistleblowing service is determined to tackle. When it comes to women in the ambulance service being pressured into sexual favors, how widespread, how large of a problem do you think this is?

It is a big problem. It's a problem that we need to take incredibly seriously.

Are women safe working in the ambulance service?

I'm not confident that all women are safe working in the ambulance service at the moment, no. It's not enough just to say, shock and horror, it's dreadful. We have to take daily action.

But the problem is a historic one. When Janet was starting out as an emergency care assistant 20 years ago, she says she was blocked from progressing onto paramedic training courses.

It became evident on a social night out that sexual favors were the way to gain entry onto emergency courses. I was horrified. I expected it to be academic qualifications that would get me there. But I was told to be guaranteed on the next course, this is what you have to do.

A senior NHS spokesman called these allegations appalling and completely unacceptable, saying they expect action and dismissals against those responsible for abuse or harassment. They stressed better reporting mechanisms, training and support for staff are being brought in. But after seeing earlier sky news investigations about harassment in the ambulance service, Sarah, too, plans to quit her job this year. With little faith, the culture this embedded can ever change. Rachel Venables, Skynews.