The NHS is using non-disclosure agreements (NDAs) to silence staff who raise complaints of sexual harassment and bullying in the workplace, it has emerged.

A Freedom of Information request submitted by The Guardian newspaper, showed that University Hospital Southampton NHS trust and the University Hospitals of Derby and Burton NHS foundation trust had handed out six gagging orders in the past five years.

The new figures also showed that the numbers of doctors accused of bullying and sexually harassing colleagues has risen nearly 40 per cent since 2013-2014.

Previously the health service has used NDAs to stop whistleblowers from raising patient safety concerns but it is the first time confidentiality agreements have emerged relating to harassment.

The Telegraph has been campaigning to prevent the actions of rich and powerful individuals and organisations being hidden behind confidentiality agreements.

University Hospital Southampton said their agreements related to the terms of the settlement and did not stop individuals highlighting issues of public interest.

Dr Neil Pease, executive director of workforce and organisational development at University Hospitals of Derby and Burton NHS Foundation Trust, also told The Guardian : “There are times when both the trust and a member of staff may want to keep details relating to sensitive employment matters private.”