Complaints about ambulance delays have risen, and the service has warned that there have been 'extraordinary levels of hospital delays' in Norwich this month.

A report to the East of England Ambulance Service's board reveals that bad weather and the delays at the Norfolk and Norwich University Hospital, in particular during the week ending February 12, are expected to hit its ability to meet targets.

In the week ending February 19, more ambulances than ever were waiting outside the region's hospitals, with nine per cent waiting more than 60 minutes.

Ambulance crews aim to hand patients to accident and emergency staff within a maximum of 15 minutes – but from 2009/10 to 2010/11, the N&N's transfer time increased from 12 minutes and 11 seconds to 18 minutes and five seconds.

N&N medical director professor Krishna Sethia said: 'We have a larger proportion of emergency admissions than other trusts in the region, cover a large rural area with an elderly population and we look after a high number of complex cases.

'We triage all patients within 15 minutes of arrival by ambulance to ensure that the sickest patients are prioritised for treatment. We are also working closely with other health partners so that more support is available to keep patients well at home and avoid emergency hospital admissions.

'Improving ambulance turnaround times requires a whole system approach and we are working together with the ambulance trust and other members of the health and social care community and actively looking for areas to improve.' A spokeswoman for the ambulance service said: 'There has been, and continues to be, a significant amount of work to reduce back up times and we expect to meet our target for the year end. Long term improvements have been made to help meet the targets more consistently going forward.

'We completed the roll out of a new computer dispatch system in the remaining two control rooms last year and while any change in a key system inevitably has a short term impact this is expected to improve performance in the longer term. More in depth assessment and appropriate treatment over the phone for people with minor injuries who don't need an ambulance means more vehicles can now be available for patients who do need them and closer working with hospitals to reduce handover delays frees up crews for other calls.'

The service received 163 complaints in the final three months of last year, of which 40pc related to delays, an increase from the previous quarter.

However, the service says it received nearly 500 compliments, and the proportion of complaints was low compared to the 220,769 emergency calls made during the same period.