A Londonderry ambulance was involved in a "freak accident" yesterday when a wheel came off while it was responding to an emergency call.
The ambulance was travelling to Altnagelvin Hospital with a patient when the driver heard a noise at the rear of the vehicle at approximately 3am.
He stopped on Northland Road and called for a mechanic to examine the problem. A second ambulance was called to take the patient to the hospital.
The ambulance was being taken in for repairs when one of the rear double wheels came off.
The Northern Ireland Ambulance Service has asked for a report on what happened.
NIAS vehicles are subject to government guidelines for replacement, which takes place every seven years or 140,000 miles.
A spokesman for NIAS said: "NIAS has in place stringent servicing and maintenance schedules whereby A&E vehicles are serviced every 12,000 miles. This vehicle was last serviced in March 2007 and has covered 10,000 miles in the interim.
"NIAS vehicles are subject to government guidelines for replacement and this particular vehicle falls within these guidelines."
The spokesman sought to reassure the public of the safety of NIAS equipment.