Wiltshire Police chiefs are waiting to hear if they will be forced to break the current helicopter contract with Wiltshire Air Ambulance.

The contract for the joint police helicopter/air ambulance runs until December 2014.

The Home Office is due to confirm today details of a new national police air service which would see police forces sharing helicopters.

The number of police helicopters would reduce by a third to 24 operating out of 22 bases. In Wiltshire the location would be at RAF Colerne rather than police headquarters in Devizes, where the Wiltshire helicopter is.

When the proposals were announced in October 2010 the national police air service was due to be up and running in April 2012.

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

"We currently have contractual arrangements in place with Great Western Ambulance Service (GWAS) in relation to the Wiltshire Police helicopter and Wiltshire Air Ambulance. These arrangements are scheduled to run until December 2014 and 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. Our current arrangements, working collaboratively with GWAS and the Air Ambulance Trust, work extremely well for the benefit of the Wiltshire public and we would hope any national scheme can include a similar collaborative arrangement for Wiltshire."