The bariatric vehicles, which are now in service across North Wales, have been specially developed to cater for overweight people with an extra wide strengthened stretcher and a winch.

The man behind their design is Welsh Ambulance Service National Fleet Manager Tony Cowley, based in Wrexham, who first developed them in his previous role with the ambulance service on Merseyside.

Now the specially-built vehicles are being introduced across Wales and also in North West England and other ambulance services across the country are already showing interest.

In all, eight bariatric ambulances have been deployed in Wales, three each in South East and North Regions and two in Central and West and they are proving a valuable addition to the Welsh Ambulance Service fleet.

They are based on the Renault Master van but custom-modified by specialist ambulance vehicle firm Wilker UK at Sandbach in Cheshire.

Those modifications include a special stretcher capable of carrying 50 stones, or 700lbs – about what the Welsh front row weigh in at – and with extra fold-out wings to accommodate wider bodies.

They also have a winch fitted to help reduce manual handling by staff as much as possible.

They are part of the Welsh Ambulance Service's new High Dependency Vehicle fleet, specialist vehicles which can deal with non-life-threatening calls, freeing up emergency vehicles.

But these vehicles are specially designed to deal with one of modern society's besetting problems, obesity and Tony Cowley said: "We have seen a 25 per cent increase in this sort of patient.

"Having vehicles like this enables our staff to transport patients with this medical problem without injuring themselves or the patient while also preserving the patient's dignity.

"They are part of our High Dependency Service which frees up emergency ambulances by transporting patients who don't need a blue light full-on emergency response.

"But if there is a call to transport a patient who is above the normal criteria, that is clinically obese, more than 20 per cent above normal body weight, then these vehicles come into their own.

"A conventional stretcher will only carry a load of up to 25 stone but these Megassist stretchers can cope with twice that and help us deal with every aspect of our patients' needs irrespective of size or weight.

"In addition our staff are trained in the use of this equipment and in dealing with the clinical needs of the patient in the most appropriate way."

The Renault Master was chosen for its load-carrying ability – it can cope with a gross weight of almost four tons so that it is well within its capacity to carry a patient and staff, and it also has a low floor making access for patients easier.

Mr Cowley added: "It is important that we look after patients and also that we look after our staff.

"Three-quarters of all ambulance staff used to retire early because of back and other physical problems but the equipment on these ambulances, as on our other new vehicles, reduces lifting to a minimum and safeguards our people."

The eight bariatric vehicles are part of an ongoing updating of the Welsh Ambulance Service fleet.

An initial £16.9 million from the Welsh Assembly Government announced in October 2006 paid for 119 new state of the art emergency ambulances, 67 Patient Transport Service vehicles and 41 Rapid Response vehicles.

A second consignment paid for by an additional £6.3 million from the Welsh Assembly Government in March includes the eight bariatric vehicles as part of a consignment of 32 new emergency ambulances, 30 Patient Care Service vehicles and nine new RRVs.

As well as the bariatric ambulances for dealing with the obese the money will go towards further boosting the service's fleet with the provision of some very special vehicles.

Mr Cowley said: "The Welsh Assembly Government is now seeing the fruits of all the hard work the Ambulance Service has been doing and in supporting us have shown they have the confidence to further invest in us.

"The Ambulance Service is well and truly getting tooled up for the job."

Among the 16 specialist vehicles are three for command and control and welfare which can be used for major incidents and outdoor events such as concerts and large open air gatherings and which have catering and toilet facilities.

Mr Cowley added: "This gives us the opportunity to give our staff somewhere to have a rest because in this day and age it's important that we look after them and they will also bolster our command and control capacity."

Ambulance Service deputy chief executive Mike Cassidy said: "Our staff have some fantastic skills and we're very, very proud of what they do and now we're in the process of making sure we've given them what they need to do the job.

"It's been a tremendous accolade for the Welsh Ambulance Service Trust that we've had this investment – it's a vote of confidence in us and one we're determined to live up to."