In September 1971, Keith Joseph, then Secretary of State at the Department of Health and Social Security, introduced Invalidity Benefit in the National Insurance Act 1971.
The Prime Minister of the day, John Major, had complained about the burgeoning caseload, saying: "Frankly, it beggars belief that so many more people have suddenly become invalids, especially at a time when the health of the population has improved".
Tania Burchardt from the London School of Economics has described the 1970s and 1980s as decades that were notable for an "improvement of the coverage of earnings-replacement benefits", and produced data showing that a disabled person who was unable to work would be receiving more money in real terms than they would have done in the 1950s and 1960s.
[9] A number of reasons have been proposed for this rise: A study published in the British Medical Journal suggested that the decline in manual employment was the main reason for rising levels of Invalidity claims, as men who had been in a manual occupation were the most likely to be claiming Invalidity Benefit.
A report by Sheffield Hallam University showed that Invalidity Benefit claims started to rise when unemployment rose in the late 1970s and early 1980s, and argued that this indicated that many claimants were not too unwell or disabled to work, as the number of people with serious illnesses and disabilities would be expected to be constant.
[11] An editorial in the British Journal of General Practice published in 1990 argued that GPs felt pressured into giving patients sick notes because they did not have time to fully assess the patient's fitness to work, which was contributing to the rise in Invalidity Benefit claims.