The future of the West’s police helicopters and air ambulances was thrown into doubt yesterday after the Government announced a radical overhaul of the way the emergency services work.

Police minister Nick Herbert is to set up a National Police Air Service, which will take over from the historic ad-hoc arrangements for police helicopters, and that is almost certain to mean a cut in the number of police helicopters currently serving the West.

It will also mean an uncertain future for Wiltshire’s air ambulance, which is one of only two emergency helicopters shared with the police.

There are currently 32 aircraft at 30 air bases across the country, but this will be cut to 22 bases serving 24 aircraft – saving £15 million a year from police budgets.

At present, Gloucestershire Constabulary share a police helicopter with the Avon and Somerset force which is based at Filton, near Bristol, while Wiltshire police share a Devizes-based helicopter with the county’s air ambulance charity.

But the new National Police Air Service will see one chopper based at Colerne in Wiltshire serving most of Gloucestershire, Wiltshire, Avon and Somerset. The nearest other NPAS helicopters will be at Bournemouth in Dorset, Benson in Oxfordshire, Exeter Airport and Birmingham Airport.

Mr Herbert will say the National Police Air Service (NPAS) will provide forces with access to helicopters 24 hours a day, 365 days year, rather than a force’s helicopter being out of use for weeks for repairs.

“Chief officers of all forces in England and Wales have given their support to the proposal, as have the overwhelming majority of police authorities in principle. But to get the full benefits, the commitment of the whole of the police service in England and Wales is needed,” Mr Herbert said, adding that he was prepared to force through changes even if the police did not agree.

What the implications will be for the Filton and Devizes-based helicopters remains uncertain. Wiltshire police have an agreement with the Wiltshire Air Ambulance charity until the end of 2014, which police chiefs said they were keen to stick to.

At present, the charity has to raise around a million pounds a year to pay for its half of the helicopter – if the deal ended it would have to raise more than £2 million to keep a standalone air ambulance in the skies over Wiltshire.

Wiltshire Police Authority chairman Christopher Hoare said: “We are currently in discussion with the NPAS as to whether any national arrangement would serve the public of Wiltshire and these negotiations are still ongoing.

“We would wish to see NPAS committing to honour the contract. The charity are being kept fully sighted on the negotiations that are taking place.”