A Norfolk hospital was forced to set up a major incident tent outside its doors as it struggled to cope with the number of admissions.

The mobile treatment area at Norfolk and Norwich University hospital (NNUH) was deployed after queues of 15 ambulances waiting to hand over patients formed on Monday. The East of England ambulance service trust (EEAST) said vehicles queued for more than three hours and the delays prevented them from attending other incidents.

The tent, described by the hospital as a precaution, was not used to treat any patients but the fact that it was set up at all will raise questions about the hospital's ability to cope with the level of demand. In March, 17 ambulances were left queueing outside the hospital after new emergency attendances and admissions described as "off the scale" by the NNUH's director of medicine and emergency care.

EEAST has been under fire for slow response times in Norfolk with ambulance officials highlighting the ongoing issues of queues at the hospital as a contributory factor, according to the Eastern Daily Press.

Oskan Edwardson, associate director of special operations at EEAST, said: "Between 11am and 8pm the trust had an average of between six and 15 vehicles queuing for up to three-plus hours. Clearly this led to ambulances not being available to respond to other patients in the community. We worked closely with the hospital and CCG [Clinical Commissioning Group] throughout the afternoon and deployed the trust major incident tent to help release ambulances back on to the road. The trust is pleased that this issue is now resolved following much hard work by the hospital and the ambulance service and that in the end no patients were required to be treated in the major incident tent at this time."

He said that despite the use of a major incident tent, a major incident was not declared.

The NNUH chief executive, Anna Dugdale, said: "We were extremely busy over the weekend. We made a decision with the ambulance trust to put the tent up simply as a precaution at about half past six last night. We agreed by quarter past eight that we didn't need it."