'We are an emergency service, not a taxi service.' That was the message from managers in the ambulance control room in Hellesdon as they try to cope with a year-on-year increase in calls.

999 is meant to be for emergencies, but many of the calls the East of England Ambulance Service receive are far from life-threatening or urgent, say staff.

Jo Metcalfe-Hume, who has been a call handler in the control room for the last 18 months, said: 'On a Saturday night you get a lot of people who have had too much to drink and call 999 for a taxi. We get people that have cut their finger and some people phone with a headache or toothache.'

The NHS trust has come under fire over the last year for failing to hit its response targets for the most urgent 999 calls and has been told to improve its performance by the healthcare regulator, the Care Quality Commission.

However, only half of the 700 calls put through to the Norwich HEOC (Health Emergency Operations Centre) on a daily basis require an ambulance to attend patients with the other half being referred to their GP for further treatment or being told to make their own way to A&E.

Around 30 call handlers, dispatch operators and medics are based in the control room at Hellesdon at any one time, which is operated 24 hours a day, seven days a week, and are the first people a patient will speak to when they need medical help.

The Norwich HEOC takes 999 calls for the whole of Norfolk, Suffolk and Cambridgeshire and is a hive of activity.

Call handlers answer around sixty 999 calls within a 12-hour shift and staff are often left frustrated by people phoning the emergency number with minor ailments.

Brett Norton, duty manager at the Norwich HEOC, said: 'As much as we try to predict demand, there is no pattern. Every day is busy for us these days and we are always experiencing high levels of demand. There are alternatives to calling 999 – there is 111, GP services and out of hours.

'It is frustrating because it impacts on our responses to life-threatening cases. We try to send them to a more appropriate pathway. However, it puts an added pressure on the service. We maintain our focus and make sure we are dealing with calls in an appropriate way,' he said.

Staff work 12-hour shifts in the control room, off Hospital Lane, with around 10 call handlers on duty at any one time who take the initial call from BT when someone phones 999 and asks for the ambulance service.

Call handlers, who are not medically trained, follow a rigid set of questions – called the Emergency Medical Dispatch Protocol – to determine the type of response required. Dispatch operators are charged with ensuring the nearest and most appropriate ambulance crew or rapid response vehicle reaches urgent cases across Norfolk and Suffolk.

A large number of calls are also referred to the clinical support desk – made up of paramedics, nurses and emergency care practitioners – who phone back and give medical advice to people who do not urgently need an ambulance to take them to A&E.

Matt Broad, below, Norfolk general manager for the East of England Ambulance Service, said the trust was dealing with a 3pc year-on-year increase in 999 calls.

'We look at demand based on historic data, but it does not account for a significant road traffic collision where we may get ten to 15 calls for one job. Mondays are a busy day after the weekend with a lot of GP urgent admissions and Fridays, Saturdays and Sundays are days of rest for the public and we are here 24 hours a day.

'We assume that when people phone 999 it is going to be a life-threatening and we dispatch the nearest response as soon as we get the call. If the priority changes after assessing the call we can stand down if it is not a life-threatening call,' he said.

A large computer screen in the control room tells managers how many call handlers are on duty, how many are free to answer 999 calls, and how many people are waiting on the line, which turns from green, to amber, to red if the trust gets a surge of calls and can not keep up with demand. Another screen also displays the NHS trust's response to key ambulance service targets.

Mr Broad added: 'This is the critical part of the ambulance service and the good work they do dictates what treatment the patient is going to receive. It is really important to support the control room. This is the hub of the ambulance service and if we get the process right here, it has a knock-on effect on how we deliver our care. There is a good team spirit and they work in a team and generally work with the same people,' he said.

Calls categorised as red 1 or red 2 incidents – life-threatening incidents such as suspected heart attacks, strokes and unconscious patients – require the trust to reach 75pc of patients within eight minutes and get a transportable resource to 95pc of them within 19 minutes.

Green 1 calls require a response within 20 minutes, a 30-minute response for Green 2, a telephone assessment within 20 minutes for Green 3 calls and a telephone assessment within 60 minutes for Green 4 incidents.

Another part of the East of England Ambulance Service control room in Hellesdon is dedicated to the new 111 phone service for patients in Norfolk who require non-urgent medical assistance and advice and is available 24 hours a day, 365 days a year.

Do you have a health story for the Norwich Evening News? Call reporter Adam Gretton on 01603 772419 or email adam.gretton@archant.co.uk