A volunteer ambulance driver fears patients could suffer if parking attendants at an Oxford hospital carry out threats to clamp his vehicle.

John Tompkins was waiting to drive three patients back to their Banbury homes when he was given a final warning not to park without paying at the Churchill Hospital, Headington.

As a volunteer driver for Oxfordshire Ambulance Trust, the former RAF engineer is allowed to wait at the hospital's pay and display car park without buying a ticket. But although he was displaying green volunteer driver windscreen badges, parking attendants still stuck a notice on his car threatening to clamp him.

The Oxford Radcliffe Hospitals' head of facilities, Trevor Payne, said: "We are glad this issue has been brought to our attention, and are aware that there have been some problems. These are currently being investigated.

"We recognise that voluntary car ambulance drivers carry out a valuable service for the trust and may be on site waiting for long periods of time.

"Car parking on our hospital sites is extremely limited and our site redevelopment work is adding to current difficulties.

"However, we have made special arrangements for parking on site for car ambulance drivers."

Mr Tompkins, of Green Lane, Arncott, near Bicester, said: "I asked myself why I was becoming involved in the stupid, petty and dictatorial attitude of a few individuals, using threatening notices with little consequence.

"Can you imagine what would happen if an ambulance or an ambulance car were to be clamped? At the end of the day, whatever the situation, the patient is the one that would suffer."

Mr Tompkins has been a volunteer driver for 18 years and uses his own car three days a week to take patients on a 50-mile round trip from their Banbury homes to Oxford hospitals.

He is given 28p a mile expenses by the ambulance trust.

Parking attendants gave him the warning notice on Saturday, January 8, while he waited for three kidney failure patients having vital dialysis to clean their blood. Mr Tompkins has complained to David Highton, chief executive of the Oxford Radcliffe Hospitals NHS Trust, which is responsible for the Churchill.

He said: "I would hate to be the first to be clamped, because all hell would break loose.