The 878,300 who decided not to have an official assessment of whether they were fit for work was more than a third of the total number of people claiming sickness-related benefits.

The statistics also revealed that some claimants cited conditions such as “blisters”, “sprains and strains” and “acne” as preventing them from having a job.

More than 46,120 people claimed incapacity benefit because of “behavioural disorders due to the use of alcohol” while 29,130 claimants cited drug use.

Ministers said the figures showed the full extent of how millions had been “trapped on welfare” for decades.