Number of patients having stomach-stapling surgery on the NHS nearly doubles in just one year

Figures show there were 3,459 gastric bypass operations last year - up from 2,448 the year before.

Each operation costs the NHS around £7,000, meaning more than £ was spent on such surgery in 2007.

The number of people having stomach-stapling surgery has more jumped to 41 per cent

Andrew Lansley, shadow health secretary, said the figures show Labour is failing to tackle obesity

Around a quarter of British adults are obese, but gastric bypasses are normally only performed on patients who are so overweight that their life is in imminent danger from heart attack or stroke.

The procedure involves reducing the capacity of the stomach and bypassing part of the small intestine.

This reduces the capacity of the body to take in food, meaning the patient feels full more quickly.

The latest statistics were revealed as a result of parliamentary questions asked by Liberal Democrat health spokesman Norman Lamb, who said: 'The Government's failure to tackle rocketing obesity is one of its biggest embarrassments.

‘Obesity surgery should only be used in very extreme cases.

'The Government is now spending an enormous amount on treating obesity and not nearly enough on prevention.'

A spokesman for the Department of Health said: 'It is up to primary care trusts to determine the most appropriate methods to deliver health care to their populations. Surgery is always a last resort when all appropriate non-surgical measures have been tried.'