Tougher criteria mean the total of 20,660 incapacity benefit claimants in the Capital will be slashed by about 40 per cent.
Around 2300 will be forced on to Job Seekers Allowance and 4900 will be removed from benefits altogether.
The study by academics at Sheffield Hallam University calculated that in Scotland, the current total of 275,000 men and women on incapacity benefits would be cut by 115,000 by 2014.
The figures are based on pilot studies and the Department for Work and Pensions’ own assumptions about the impact on benefit claimants.
The study said that while some people would find work, there was little reason to suppose the big fall in claimant numbers will lead to significant increases in employment.
It warned: “Incapacity claimants often face multiple obstacles to working again and their concentration in the most disadvantaged communities means they usually have little chance of finding work.”
The researchers found that Scotland, the North of England and Wales would be most affected by the reforms, while there would be hardly any impact on the most prosperous parts of southern England.
Professor Steve Fothergill, co-author of the report, said: “The large numbers that will be pushed off incapacity benefits over the next two to three years are entirely the result of changes in benefit rules – the introduction of a new tougher medical test and, in particular, the more widespread application of means-testing from next April.
“The reduction does not mean that there is currently widespread fraud, or that the health problems and disabilities are anything less than real.
“The reforms to incapacity benefits that are under way are probably the most far-reaching changes to the benefits system for at least a generation. They will impoverish vast numbers of households and cause untold distress in countless more.”
Edinburgh East Labour MP Sheila Gilmore said the tests claimants had to go through were often producing the wrong results.
She said: “The success rate for appeals is about 40 per cent, which is much higher than you would normally expect, so there is concern that people are losing benefits who should not be.
“And we are currently in a period when the jobs are not out there anyway, so people are anxious because their chances of getting work are fairly slim.”