About 60 unpaid volunteers are manning 14 ambulances in Sussex

Sussex Ambulance NHS Trust has confirmed that members of the St John Ambulance and the Red Cross are being called on to help regular crews.

The move has been condemned by ambulance workers' unions as undermining morale in paid paramedics.

While ambulance services across the country make use of volunteers to make up for staff shortages, Sussex is unusual in sending them to 999 call outs rather than restricting them to non-life-threatening situations.

From the patients' point of view, they have somebody there quicker than they would do normally to provide life-saving treatment Andrew Parr, Sussex Ambulance NHS Trust

About 550 emergency calls are received each day in Sussex, of which about 70 are the most urgent - category A, or life-threatening.

The trust said there were 30 Red Cross and 30 St John Ambulance staff manning 14 vehicles in use across the county.

Andrew Parr, of the Sussex Ambulance NHS Trust, defended the use of volunteers on 999 calls.

He said: "If they go on a category A call they are immediately backed up, as is any other person who first responds to that sort of life threatening call.

'Plugging a gap'

"But it means from the patients' point of view, they have somebody there quicker than they would do normally to provide life-saving treatment."

The trust has been training and recruiting St John Ambulance volunteers for several years to support paid staff.

Dr James Walsh, Sussex St John Ambulance Commander, said: "Our volunteers are filling a gap that they've done for over 30 years in ambulance services up and down the country and particularly in Sussex where they are called upon by the ambulance service.

"It is in no sense a competition or anything like that - they are plugging a gap."

But David Davis, branch officer for the Unison union, said: "Our members like to think of themselves as professionals - and indeed they are.

"Therefore, to see someone who is doing the same job on a voluntary basis is not necessarily good for morale."