He also complained that too many people climbed aboard what he called the "incapacity benefit train" after being signed off work by their GPs without a proper assessment.
Mr Blunkett insisted his mission was not to penalise the disabled but to improve their lives by helping them to return to work, rather than spend their days watching television. "If we watched daytime television all day, we'd all be depressed," he said.
His remarks mark the start of a new government campaign to bring down the cost of incapacity benefit, £12bn a year being claimed by 2.7 million people - four times the number drawing the equivalent benefit a quarter of a century ago.
But others have warned that Mr Blunkett's zeal for cutting the welfare bill could create real hardship, particularly as it coincides with a new attack on benefit fraud.
The Government's own figures show incapacity benefit is not a major target for fraud, most of which is directed at income support, jobseekers' allowance, and housing benefit. But Mr Blunkett believes welfare reform and fraud are interlinked because the excessive complexity of the system allows claimants to cheat. He also issued a warning yesterday that taxpayers will tolerate the high cost of welfare only if they are satisfied that benefits are going to those who need them.
A report yesterday from the Commons Public Accounts committee estimated fraud and errors in the benefits system as a whole were adding £3bn to a total annual welfare bill of around £109bn. "The astronomical scale of the amount of benefit money being lost through fraud and error is vividly brought home to taxpayers by the astonishing fact that the figures are rounded to the nearest half a billion pounds", the committee chairman, Edward Leigh, said.
But on Thursday, the benefits minister James Plaskitt will reply with a 30-page report claiming that the Government has managed to cut the cost of fraud to £900m - which means that for the first time, it is below 1 per cent of the total cost of welfare. Mr Blunkett will issue a Green Paper on welfare reform, targeted at getting people drawing incapacity benefit to go back to work.
Yesterday, he chaired a symposium on welfare reform in the National Liberal Club in London, as part of the consultation process for his Green Paper. It may also have been timed to demonstrate that he is still focused on his job, when curiosity about his private life has been revived by last night's screening of A Very Social Secretary on Channel 4's new channel, More4.