NHS inspectors are concerned that paramedics are often prevented from dealing with 999 calls because of hold-ups at Oxford's John Radcliffe Hospital.

A report published on December 12 by the Commission for Health Improvement said crews waited up to six hours to transfer patients to the JR casualty unit.

On one occasion delays meant 11 ambulances were waiting at the hospital, in Headington.

But the trust and the Oxford Radcliffe Hospitals NHS Trust, responsible for the JR, claim to be tackling the problem.

The CHI report said: "Most crews wait more than 15 minutes and can wait up to six hours.

"As a result, patients wait in A&E corridors on an ambulance stretcher for considerable periods of time before being admitted to hospital.

"Patient privacy and dignity is compromised.

"The ambulance trust has made a number of formal complaints to the hospital about patient care being compromised while awaiting handover.

"At the time of the review there was no clear agreement between the two trusts about ownership and liability for patients in these circumstances, and they are seeking legal advice."

Ambulance chief executive John Nichols said: "We've been working hard with the ORH to resolve this issue and I'm confident that between us we now have a range of agreed new protocols which ensure both organisations can protect patient care."

He said both trusts were being "much more proactive about managing a sudden influx", alerting each other when they became busy. CHI praised ambulance staff's enthusiasm and commitment to improving patient care, and complemented them for listening to feedback and making changes to improve services.

CHI also highlighted training -- including a paramedic degree developed with Oxford Brookes University -- as an example of good practice.

It praised technological improvements, like the digital satellite navigation system, and commended the use of motorcycles to speed up 999 response times.

Mr Nichols said: "This is a positive report which shows our staff are caring professionals who always put the patient first.

"It also shows that as an organisation we work hard to train and develop our staff."