Mr Stevens, the chief executive of the health service, said obesity was a problem that could be tackled provided schools, parents, the NHS and the food industry all 'got their act together' and worked in unison.

In a direct attack on last week's EU ruling - which said fatness could constitute a disability - Mr Stevens said such fatalistic attitudes to the issue were "daft".

Instead, he urged millions of people to put Christmas indulgences behind them, and take action to shed the pounds.

"The ghost of Christmases past reminds us that 20 years ago we didnt have these problems as a nation, Mr Stevens said.

"The ghost of Christmases future tells us that if we get our act together - as the NHS, as parents, as schools, the food industry - we can get back in shape."

He called on individuals to take concerted action and suggested attitudes needed to change to prevent the country sleepwalking into the worst public health emergency in at least three decades.

"Rather than recent daft judgments by the European court practically pretending that obesity is inevitable, in England in 2015 we're going to start proving that it isn't," he added.

The new figures - comparing 26 EU countries - show that in Europe, only Hungary now has higher obesity levels than Britain.

In total 24.7 per cent of Britons are now obese, compared with a European average of 16.7 per cent, the figures from the Organisation for Economics and Co-operation disclose.

Six EU countries now have obesity levels less than half those in the UK, the figures show. Italy, Bulgaria, Sweden, the Netherlands, and Austria all have obesity levels of less than 13 per cent, with the lowest rates in Romania, at 7.9 per cent.

In the EU, only Hungary has higher rates of adult obesity than the UK, at 28.5 per cent.

Mr Stevens promised to introduce the first ever national programme to target millions of people at risk of diabetes, because their weight is creeping up.

Official statistics show rates of obesity have soared in two decades, rising from 15 per cent in 1993 to 25 per cent now. Almost two thirds of adults are either overweight or obese.

Earlier this year, a major study suggested that one in three Britons has borderline diabetes, putting them at high risk of developing the condition.

The NHS spends 10bn a year treating diabetes, with 3 million sufferers, the majority of whom have type two diabetes, which is linked to obesity.

Mr Stevens said targeted schemes to prevent obesity, by losing weight, had been proven to work, and now needed to be introduced nationally.

"Thats why the NHS is going to be funding a new national programme, proven to work, that will offer tens of thousands of people at risk of diabetes proper support to get healthier, eat better and exercise more," he said.

Major research has found that losing just 5 to 7 per cent of weight can reduce the change of diabetes by nearly 60 per cent, he said.

Mr Stevens said: "If this was a pill we'd be popping it - instead its a well-designed programme of exercise, eating well and making smart health choices, and we're going to start making it available free on the NHS."

Such schemes could begin saving the NHS money within three years, experts suggested, reducing the costs of illnesses associated with diabetes and its complications.

NHS organisations which have brought in successful local schemes to prevent diabetes will be asked to register their interest in designing the national programme by the end of the month.

Other schemes backed by Mr Stevens will see companies asked to reward staff who lose weight with shopping vouchers and prizes.

The chief executive of NHS England, who took up post in April has made it a personal mission to prioritise obesity prevention, after losing almost three stone.

Mr Stevens said he had put on 40 lbs while working in the United States, in private healthcare, but was spurred into action by an workplace scheme which gave staff financial incentives to lose weight.

The head of the NHS said he wants to see similar schemes introduced by private companies throughout England.

Mr Stevens said people needed a little nudge to introduce healthier habits.

Campaigners said Britain needed to make a collective new years resolution to reverse current trends, which will mean two thirds of middle-aged men are obese within two decades.

Tam Fry, from the National Obesity Forum, said: After the all the food and drink consumed yesterday and today I wouldn't be surprised if the UK had caught up with Hungary.

He urged Britons to take urgent action to shed the pounds.

We are calling for a national new year's resolution in January to tackle the aftermath of turkey, pud and cake, he said.

On current trends, 63 per cent of men in their 50s will be obese by 2034, along with 38 per cent of women, official data shows.

If average rates of obesity were brought back to 1993 levels, around five million incidences of disease could be prevented in two decades, official forecasts show.

Meanwhile, more than one third of children are now overweight or obese by the time they leave primary school, NHS figures show.