Almost two thousand people who are too fat to work have been paid a total of £4.4 million in benefit, it emerged last night. Other payments went to fifty sufferers of acne and ten incapacitated by leprosy.

Billions of pounds is being paid in benefits to people claiming to be unable to work because they suffer from depression, stress, fatigue and unknown or unspecified diseases.

The full list of ailments of the 2.7 million people claiming £7.4 billion in incapacity benefits, obtained by using Freedom of Information laws, will fuel suspicion that it is being used to keep them off the official jobless total. It will also fuel the debate over whether British workers could have been hired for more of the one million new jobs taken by migrants since 1997.

Frank Field, a former Social Security Minister, said last night that too many people were working the incapacity benefit system to avoid work. “It is a racket, which governments have allowed to exist for far too long. I do not blame people for working the system, it is the job of politicians to stop them doing it.”

Mr Field added that because job seeker’s allowance is lower than incapacity benefit, there was an incentive for people to try to be classified for the higher benefit.

The number on incapacity benefit has more than trebled since 1979 but in recent years it has been broadly stable at about 2.7 million. In the past 12 years, however, there has been a dramatic shift in the illnesses for which people are being given the benefit: 40 per cent now claim for mental health problems compared with just 20 per cent in 1995.

Mr Field said: “The big change over the last decade has been into illnesses which largely defy a clear medical classification: depression, dizziness and such. It is a move from the tangible illness to the intangible.”

The complete list of the 480 different illnesses and complaints for which people received incapacity benefit in February were released by the Department for Work and Pensions. More than £2 billion was paid in 2006-07 for mental health complaints, including £518 million to those with what are described as “unknown and unspecified” diseases.

Overall more than £1.1 billion was paid to people suffering from a depressive episode plus a further £276 million to the estimated 116,000 claimants with “other anxiety disorders” and £122 million to the estimated 50,000 suffering from a “reaction to severe stress”.

A total of 15,600 people received benefits for “malaise and fatigue” and a further 8,100 for “dizziness and giddiness”. The figures disclose that 4,000 claimants had headaches, 2,700 migraines and 1,890 suffered from eating disorders. About £100,000 in benefits went to those with acne and a similar amount to 60 people with “nail disorder”. Nausea and vomiting cost £2 million in benefits for 900 people.

Peter Hain, the Work and Pensions Secretary, said last night that rigorous checks were in place before someone was granted incapacity benefit. “No one is entitled to incapacity benefit automatically on the basis of a diagnosis,” he said.

“Currently, there are many people sitting at home in the belief that they are unemployable because they do not think their illness or medical conditions can be catered for in the work-place but this is just not the case. Many people with such conditions are perfectly able to take up successful careers, if the right support is in place. That is why we are changing the system to focus on what people can do, not what they can’t.”

Matthew Elliott, the chief executive of the Taxpayers’ Alliance, said: “Many incapacity claimants are clearly taking advantage of the good nature of their GPs. There is a huge difference between not being able to work and not feeling like working. All of us sometimes don’t feel like working but we make the effort and put in the hours.”

Incapacity benefit is available to anyone under state pension age who cannot work because of illness or disability. A person becomes eligible after they have been on statutory sick pay for eight weeks. The amount payable ranges from between £61.35 a week to £81.35 a week, compared with £59.15 jobseekers allowance.

The employment and suport allow-ancw will replace incapacity benefit next year in an attempt to get more people into work. A revised health test will focus on a person’s capability rather than incapacity for work.

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