Hundreds of thousands of disabled people will see their benefits axed or cut in the next three years, the Government has said.
Ministers are reforming disability payments because, they say, some claimants have not been recently assessed and may now be suitable for some work.
They believe that by cutting benefits for some recipients they can divert money to those in more need, scrapping the 20-year-old disability living allowance (DLA) and replacing it with personal independent payments (PIPs).
Disabled people's minister Esther McVey told the House of Commons: "By reforming the system, ensuring it is fit for the 21st century, we can use the money we spend on disabled people more efficiently and effectively to help those most in need."
She added: "By October 2015 we will have reassessed 560,000 claimants. Of those, 160,000 will get a reduced award and 170,000 will get no award. However, 230,000 will get the same or more support."
Ms McVey said claimants receiving lifetime or indefinite DLA would not be reassessed until October 2015 at the earliest - after the next general election.
Labour backed reform but shadow minister Anne McGuire insisted: "The assessment needs to be the right one."
The annual bill for DLA is £13.2 billion a year, shared among 3.2 million adults.
In her Commons statement, Ms McVey said the changes would make the system "more transparent, objective and fair" and insisted that the Government had listened to the "huge" response to its disability benefits consultation.
She told MPs the checks would be introduced more gradually, adding: "We are now to undertake a significantly slower reassessment timetable to ensure we get this right. It will be phased in, starting with the North West and parts of the North East of England from April 2013."