Uncertainty surrounds who will commission the county’s ambulance service when Primary Care Trusts are abolished.

The PCTs are due to be scrapped in April 2013 and replaced by Clinical Commissioning Groups (CCGs), comprising mainly GPs, under the Government’s shake up of the NHS.

Great Western Ambulance Service (GWAS), which covers Wiltshire, Avon and Gloucestershire, is funded by the seven PCTs in the patch. Under the new arrangements there will be nine CCGs.

GWAS is looking to merge with South Western Ambulance Service, which covers Somerset, Dorset, Devon and Cornwall.

In South Western Ambulance Service’s patch there are seven Primary Care Trusts and these will be replaced by 11 CCGS.

In both GWAS and South Western areas one PCT represents the others (called the lead commissioner) to negotiate the funding contract with the ambulance service.

NHS bosses said it had not yet been decided how a lead commissioner for the CCGs would be chosen. A spokesman said no decisions had been made at this stage concerning CCG commissioning of ambulance services in 2013/14.

Ken Wenman, interim chief executive of GWAS and chief executive of South Western Ambulance Service, admitted he was concerned about how the future commissioning arrangements would work under the CCGs.

At a public meeting of Wiltshire Involvement Network at Devizes Sports Club last month he said: "What we are planning is for the GPs to have a lead commissioner looking at the whole service, not just their patch."

The Times asked how one CCG commissioning ambulance services on behalf of all the other CCGs in its patch would ensure that all CCGs were satisfied with what is commissioned for them.

A spokesman for NHS Wiltshire replied: "Lead commissioners have an important responsibility to work with their commissioning colleagues within the area to ensure that local needs and circumstances are reflected in the contract and that services and performance are of the highest standard."

Albert Weager, chairman of the joint working group for Local Involvement Networks representing patients in the GWAS area, said: "My personal opinion is there is so much uncertainty. It’s difficult to imagine how it’s going to work."

*Ken Wenman said merging GWAS with South Western Ambulance Service would lead to better performance.

He told a public meeting of Wiltshire Involvement Network in Devizes: "South Western is one of the best performing ambulance services. It has always met its performance standards over the past six years and financial targets. We believe the two organisations together will be a stronger organisation.

"We will achieve the ambulance service quality indicators in the medium term. We want to achieve all the response times in the first year of operation. We want to deliver combined management costs of six per cent in the medium term, GWAS spends ten per cent of its income on managers while South Western spends six per cent."

He responded to concerns by retired ambulance staff in Wiltshire, Ian Hunt of Trowbridge and Dennis Overton of Hilperton, who fear ambulances will be sent over the county border into South Western’s region.

Mr Wenman said: "There’s absolutely no plan to transfer the resources more thinly. On the contrary the only way re-investment can happen is through a merger."

Mr Wenman said if the health authorities approve the merger it could happen in October this year.