Imagine that someone you love has been injured in a serious crash.

They are on the M5 between Portishead and Clevedon and have suffered head injuries.

A land ambulance arrives and the paramedics take them directly to Weston General or the Bristol Royal Infirmary – the closest hospitals to the scene of the accident.

It takes 15 to 20 minutes for them to arrive at the accident and emergency department, where they stabilise the patient and stop any swelling to the brain.

They then transfer them to Frenchay Hospital, a specialist centre for head injuries, a journey that takes about half an hour even at full speed.

It may be several hours before your loved one is receiving the most appropriate care for their injuries. It is not a scenario anyone wants to think of, but sadly it could happen.

In the past, patients would be taken by ambulance to the nearest hospital, not the facility that would best treat their condition.

But now that the former Avon area has its own dedicated air ambulance team for the first time ever, the chances of people receiving the best possible care in the most appropriate setting are more likely.

Unlike most emergency air services in the UK, the Great Western Air Ambulance (GWAA), which is based at Filton Airport, carries doctors and critical care paramedics to incidents to start treatment and stabilise patients before sending them to the best hospital for their needs.

Rather than transporting patients as soon as possible, they provide care at the scene that previously was only available in A&E departments in the South West to give them a better chance of survival.

It is not replacing the more traditional ambulance, but is putting in a whole new level of care so that he sickest patients who need more help in the early stages receive it.

Danny Hopkins, director of air operations for Great Western Ambulance Service (GWAS), said: "The skills and expertise we offer are different to ambulances and in the helicopter we can get anywhere within the whole GWAS patch within 18 minutes.

"We have got a specialist team that can be delivered to an accident and can, in essence, bring A&E to the scene.

"This is about providing the best possible care. The helicopter is a faster means of getting us from A to B but it doesn't matter if we are in the car or the helicopter, it is about being able to give that care and know that no more could be done for the patient at the scene and we speed up treatment at A&E by doing it on the side of the road."

Providing that level of care does, however, come at a price – £1.3 million a year, which is why GWAA, which is backed by its own charity, wants people across the Bristol area to help them fundraise for the service, which could help anyone at any time.

Air ambulances are not funded by the NHS, even when they are providing the additional level of care. The paramedics are paid for by GWAS, but the doctors cover shifts voluntarily, and there is no money provided for kit, fuel or the helicopter itself.

GWAA is currently only flying Tuesday to Saturday rather than every day because they do not yet have the funding to fund the helicopter for the whole week.

The critical care car runs throughout the week, but there is no air support to reach emergencies.

"I don't think the public realise quite what goes into an air ambulance," Mr Hopkins said. "99 per cent of the public expect it to be funded by the NHS and ask why we are only flying five days a week and don't realise it is because we haven't got the money. Every air ambulance in the country is charitably funded."

This means the team have to be frugal in their use of the air craft and only use the helicopter when it is strictly necessary for fear of wasting their minimal funds.

Mr Hopkins said: "We filter out as much as possible so we launch as appropriate because it is an expensive resource and we don't want to waste money. The more money we spend, the further away we are from a seven-day operation."

The GWAA was launched in June and the helicopter has already been sent out on 194 calls, with 117 in the Bristol area. About 30 of these missions were halted en route.

The bulk of their work has been attending to patients after road collisions, but there have also been falls, industrial accidents, sporting injuries, burns and cardiac arrests.

In the Bristol area, about 20 people have been transferred to hospital by helicopter and generally to Frenchay because there is currently nowhere to land at the BRI and Children's Hospital. On five occasions, a member of the critical care team went with the land crew to transport a patient and there were 26 times when the crew handed patients over to a land ambulance after treating them at the scene.

Jonathan Benger, A&E consultant at the BRI and medical advisor to GWAA feels that the majority of 999 calls can be dealt with by ambulances but the critical care team can deal with a "small but significant" number of patients who would then benefit from their additional skills.

"We see our service as more of a flying hospital, or mobile care unit, taking experts from the hospital to the patient," he said.

"The team can make the difference between life or death by providing patients with drugs that are only available in hospitals, or general anaesthetic."

"Once the patient is stabilised there is more time to choose the best hospital for that particular individual rather than the nearest hospital because they are in a critical condition, and we can fly them however far it takes to send them to specialist children's or burns units and means all patients are delivered to the right hospital first time and do not have to be transferred later."

He said the critical care team also provides a swifter transition for patients when they arrive in the A&E department because there is no need to stabilise them on arrival.

"The patients can get into the scanner within 15 minutes of arrival rather than an hour because a lot of work was done pre arrival. If they need to go to ITU they can go to ITU sooner, or the operating theatre a lot more quickly than they would have been"

Paul Weir, is chief executive of the Great Western Air Ambulance Charity, which is charged with raising much of the £1.3 million.

"The fact that we have covered so many missions already demonstrates there is a real need for this service. Being such an advanced medical model, it is completely making a difference for the outcomes for patients, but the fact remains that without public support we won't be here.

"Unless we raise £1.3 million there won't be a helicopter here. We need that and we need to get up to seven days a week as soon as possible as we are only flying Tuesday to Saturday and two days a week there is not any cover. We need the public, it is their helicopter.

"There is no government funding and no lottery funding so it really is down to the man, woman and child in the street and those are the people who could be potential customers. Hopefully they will never need to use it, but the fact is, it's needed."

Mr Weir said that anyone who wants help or advice on organising a fundraising event can contact the charity for advice.