A medical charity today admitted it was struggling to keep up with overwhelming demand from obese patients for use of its ambulances.

St John Ambulance Suffolk revealed demand for its bariatric service is higher than ever, following a study into resources for obese people.

The service, which has been providing specialist transfer since 2003, receives requests from NHS Trusts throughout the UK for the use of its four tailored bariatric ambulances.

A fifth is currently being built to boost Suffolk’s fleet, at a cost of more than �70,000, but demand is increasing for the vehicles, capable of moving a patient of 70 stone with stretchers, wheelchairs, a winch and rescue equipment.

In 2010, Ipswich man Paul Mason, who weighed nearly 70st before undergoing life-saving gastric surgery, was driven 140 miles in one of its ambulances to the specialist St Richard’s Hospital in Chichester.

In the last four years, St John Ambulance in Suffolk has invested more than �20,000 in equipment and now averages 20 transfers a week.

Responding to a Postgraduate Medical Journal study into demand for specialist equipment, Keith Hotchkiss, operations manager for Suffolk, said: “This latest study clearly reveals that the tackling of obesity in the UK remains a complex problem and that facilities like ours will continue to be in demand for the foreseeable future.

“We have found a clear increase in the number of transfers of obese patients over the last four years and now find we average 20 such transfers per week.

“With every journey and undertaking, our objective is to ensure that St John Ambulance is providing care in a dignified and respectful manner which benefits both the NHS trusts and the individual patient.”

Almost a quarter of adults and one in seven children are now estimated to be clinically obese – with a body mass index of 30 or higher – costing the health service �4.2bn a year.

By 2050, more than half the UK’s of adults and a quarter of children are expected to be obese.

The study referred to a number of serious cases in the UK, including three deaths, which involved complications such as heart and ventilation problems.

But the highest number involved less serious issues like pressure sores and delays and cancellations in treatment.

Dr Chris Booth, one of the author’s of the report, said: “Obesity has exploded over the last 15 to 20 years and the NHS has struggled to keep up.

“Obese patients need specialist equipment and there are physiological and anatomical differences that staff need to be aware of.”