Media playback is unsupported on your device Media caption Nigel Wells from West Midlands Ambulance Service compares a standard and bariatric ambulance

Some patients are getting so fat that ambulance bosses are having to revamp their fleets to cope, the BBC has learned.

Every service in the UK has started buying specialist equipment, data from freedom of information requests show.

This includes wider stretchers, more lifting gear and reinforcing existing vehicles.

Many have also bought specialist "bariatric" ambulances - costing up to £90,000 each - to ferry the most obese.

These are designed so that double-width trolley stretchers for patients up to 50 stone (318kg) can be accommodated. They also tend to include hoists and inflatable lifting cushions.

Obesity rates

But the rising rates of obese and overweight patients mean even standard ambulances are having to be stocked with specialist equipment.

While these vehicles cannot take the full-range of kit that a bariatric ambulance can, they can often carry heavy-duty wheelchairs and stretchers as well as the lifting cushions on newer models.

What ambulances bosses are buying Bariatric ambulances - Specially-designed vehicle crash-tested to take heavier loads and equipped with full-range of obesity equipment. Cost: £60,000 to £90,000.

Specially-designed vehicle crash-tested to take heavier loads and equipped with full-range of obesity equipment. Cost: £60,000 to £90,000. Wider stretchers - Different makes used. Most popular sits on trolley and extends to twice the normal width. Can take patients up to 50 stone (318kg) compared to 30 stone (191kg) normally. Also used in standard ambulances but cannot be extended to full width. Cost: £7,000 to £10,000.

- Different makes used. Most popular sits on trolley and extends to twice the normal width. Can take patients up to 50 stone (318kg) compared to 30 stone (191kg) normally. Also used in standard ambulances but cannot be extended to full width. Cost: £7,000 to £10,000. Heavy-duty adjustable stretcher - No wider than standard, but able to take heavier patients and has lifting mechanism so it can be moved up and down to make it easier to get large patients on and off. Cost: £7,000.

- No wider than standard, but able to take heavier patients and has lifting mechanism so it can be moved up and down to make it easier to get large patients on and off. Cost: £7,000. Lifting cushions - Inflatable cushion which can be used to get people off floor. Cost: £2,500.

- Inflatable cushion which can be used to get people off floor. Cost: £2,500. Heavy-duty wheelchairs - Wider and stronger than standard. Cost: £400-plus.

- Wider and stronger than standard. Cost: £400-plus. Hoists - Tend to be fitted in bariatric ambulances. Used to lift obese on to stretchers. Can take weights of over 40 stone (254kg). Cost: £4,500.

- Tend to be fitted in bariatric ambulances. Used to lift obese on to stretchers. Can take weights of over 40 stone (254kg). Cost: £4,500. Stronger tail-lifts - Capable of taking weights up to 75 stone (476kg). Cost: £800.

Prices vary depending on how many and what make a trust orders.

Cushions tend to cost about £2,500 and stretchers anywhere between £7,000 to £10,000, while reinforcing an ambulance tail-lift can set a trust back £800 per vehicle.

One ambulance trust - South Central - has spent more than £1m in the last three years to upgrade nearly two thirds of its 180-strong fleet.

West Midlands is another area which has started upgrading its fleet. It has also bought four specialist bariatric ambulances at a combined cost of more than £300,000.

Nigel Wells, an operations manager at the trust said: "It is all about safety for our patients and safety for our crews. We have got a greater number of patients who are larger in size.

"A few years ago - probably only 10 years ago - your average patient was 12 to 13 stone, now that's probably 17 to 18 stone. And we quite regularly see patients around 30 stone in weight and even bigger than that."

Jo Webber, director of the Ambulance Service Network, agreed ambulance bosses had been left with no option.

"The fact is patients are getting larger and larger and ambulances need to be able to respond immediately to what could be life-threatening situations.

"Every service is having to invest money in this. It shows that some of the lifestyle changes we are seeing have a range of costs. It is not just about treating them, but the infrastructure costs as well."

The data obtained by the BBC showed the speed and pace of the approaches vary from place to place.

However, every ambulance trust in England as well as the services in Northern Ireland, Wales and Scotland confirmed changes were being made.

For example, the West Midlands, Yorkshire, the North West and Wales already have pools of bariatric ambulances and are well on the way to upgrading the rest of their fleet.

Media playback is unsupported on your device Media caption Eileen Forde: "At 34 stone a standard ambulance trolley isn't wide enough"

Meanwhile, in London ambulances bosses have been relying on a private service for which they were paying a monthly fee of £5,000 until recently.

But they have now bought two bariatric ambulances and a third is on its way. The rest of the fleet will also be getting specialist equipment in the coming years.

Jonathan Fox, of the Association of Professional Ambulance Personnel, said: "It is becoming increasingly frequent that the size of patients causes problems moving them and that in turn increases the risk of injury to staff. That is why we need this equipment. We are not just talking about those that are really heavy, even patients who are 16, 17 stone can pose difficulties."

Dr Frank Atherton, president of the Association of Directors of Public Health, added: "It is not surprising the NHS is responding this way. It is unfortunate and what we need to do is get better at trying to prevent obesity in the first place."