The Great Western Ambulance Service has confirmed that it is considering splitting the Wiltshire Air Ambulance from the county's police helicopter - three weeks after the Gazette & Herald revealed the news.

A decision will not be made for 12 to 18 months, the ambulance service said.

If it does split from Wiltshire Police the ambulance service said it would buy a new helicopter to be used as an Air Ambulance for Wiltshire, costing £2.5 million and annual running costs of £1 million, but it would not be able to fly at night and the service would hope to have its paramedics onboard the police helicopter at night.

The cost of operating the Wiltshire Air Ambulance and police helicopter is £1.36 million a year and the Wiltshire Air Ambulance Appeal contributes £350,000 a year raised through donations. The appeal money includes paying for the paramedics' wages.

The ambulance service also plans to launch an air ambulance for Avon in May costing £2.5 million but it will not be able to fly at night under Civil Aviation Authority rules and a spokeswoman said the service planned for paramedics to use the police helicopter at night.

The Wiltshire Air Ambulance and police helicopter has been in operation since 1990 and has led the way in joint working.

In a statement issued last Friday (January 5) the Great Western Ambulance Service NHS Trust said: "Over the next 12 to 18 months we will carry out a review of whether a joint police and ambulance helicopter model will be the right one for our patients in the future.

"Due to the changing nature of urgent and emergency care in the NHS, we expect to use air ambulances more and more to transfer very ill patients between hospitals as quickly and safely as possible when they need specialist treatment and surgery.

"We therefore need to examine whether a joint police and ambulance helicopter will allow us this flexibility."

The trust also said the funds raised for the Wiltshire Air Ambulance Appeal, which is around £1.2 million, will be used in Wiltshire but in addition a new air ambulance charity would be set up.

The statement said: "The Wiltshire Air Ambulance appeal committee recently concluded that it would find it difficult to sustain the current level of fund-raising. It has therefore agreed to link the Wiltshire Air Ambulance Appeal to the new Great Western Air Ambulance Charity.

"We would like to reassure people in Wiltshire that funds raised in their county will be held in a restricted account to ensure that they are used for the Wiltshire Air Ambulance. The new charity will have a great deal of fund-raising experience and will, in fact, bring extra fund-rising capacity for Wiltshire."

The trust plans to launch a dedicated Air Ambulance in Avon in May this year. It would be based in Bristol and have an accident and emergency doctor and paramedic on board.

Currently there is no air ambulance in Avon.

Ambulance service head of communications Melanie Chiswell said the cost of a new air ambulance would be £2.5 million and the annual running costs would be £1 million a year.

She said: "If we buy our own dedicated air ambulance for Wiltshire we would be looking to partner up with the police for night time flying, so paramedics would use the police helicopter at night. We are looking to do the same in Avon when we get a dedicated air ambulance there."

The ambulance service has no plans to buy an air ambulance for Gloucestershire, instead to continue using the shared aircraft with the West Midlands Ambulance Service but the new Avon Air Ambulance could also be sent to incidents in Gloucestershire.