Hospital managers say assaults on staff are taken seriously despite a low number of prosecutions of offenders.

There have been no convictions in the last 12 months of people who have assaulted hospital staff in Sussex despite a rise in prosecutions nationally.

The most recent case was in March last year and involved an incident with a nurse working for East Sussex Hospitals NHS Trust when an offender dug her nails into the nurse's arm and made it bleed.

The offender was found guilty when she appeared before magistrates, given a six-month community rehabilitation order and ordered to pay costs.

Brighton and Sussex University Hospitals NHS Trust, which runs the Royal Sussex County Hospital in Brighton and the Princess Royal Hospital in Haywards Heath among others, reported 163 physical assaults on staff in the last financial year compared to 183 the year before.

However, the number of verbal attacks and intimidating behaviour rose from 949 to 1,020.

The trust has 18 security officers in Brighton and eight at the Princess Royal, while improvements in the past year have included the introduction of more CCTV systems at the hospitals.

A trust spokeswoman said: "The trust takes any acts of violence and aggression against its staff extremely seriously and, where appropriate, does seek to prosecute offenders.

"It also offers appropriate training and counselling to staff."

Figures released by the NHS Security Management Service showed that during 2004/05 there were 759 prosecutions in England compared to 51 cases identified in 2002/03.

In the South-East there were 73 successful prosecutions.

Health Secretary Patricia Hewitt said: "Violence against NHS staff is completely unacceptable. For a minority of people to show them such disrespect is intolerable.

"Working with the NHS Security Management Service, I am determined to reduce the number of violent incidents in the NHS. Staff should not have to tolerate such abuse."