NHS staff, including ambulance workers, porters, nurses and cleaners, have been assaulted, shown pornographic images and offered money for sex, according to new research.

The Unison union said the findings of a wide-ranging survey which revealed widespread incidents of sexual harassment were shocking.

The study of more than 12,200 health workers, published on the first day of Unison’s annual health conference in Brighton, showed that one in 10 workers reported unwanted incidents including being touched or kissed, demands for sex in return for favours, and derogatory comments.

Sexual assault was reported by almost a third of respondents, while half said they have been leered at or been the target of suggestive gestures.

One in four said they have suffered unwelcome sexual advances, propositions or demands for sexual favours.

Crude “banter” or “jokes” were the most common issue, reported by three in five workers who had experienced some form of harassment, according to the research.

Despite the serious and even criminal nature of some of the incidents, half the staff had not reported sexual harassment to their employer, mainly through fear of being considered “oversensitive” or a feeling that nothing would be done.

Incidents included a 111 adviser, herself a survivor of sexual abuse, being regularly harassed on the phone by anonymous callers. The only response from her managers, was to tell her it was just part of the job, said Unison.

Unison general secretary Christina McAnea said: “No-one should ever have to endure such despicable behaviour and certainly not in their place of work.

“But NHS staff often put up with this appalling abuse, not reporting it because they don’t believe they’ll be taken seriously.

“More must be done to protect nurses, healthcare assistants, cleaners and other NHS staff from sexual harassment, reassure them their complaints will be fully investigated, and action taken against the perpetrators.

“Employers must take swift action when workers flag up incidents, regardless of whether the sexual harassment has come from a patient or a colleague. Otherwise this completely unacceptable behaviour will simply continue.”