Introducing the proposals in the House of Commons, Mr Darling said the new system would create a "single gateway" to the benefits system, and help ensure that benefits "only go to those who are entitled to them."

Mr Darling said the government aims to introduce a series of new laws starting early next year that will result in "a fundamental change in culture".

"People will no longer ask of the system: 'What can it do for me?' But will say instead, 'What can I do to help myself?'"

Employment needs assessed

Mr Darling said the reforms would "provide work for those who can, and security for those who cannot."

Ready to work, and the government wants to help him find a job

All new claimants will be obliged to attend an interview to assess their employment needs and capabilities. Mr Darling promised that no current claimants would see their benefits eroded.

There will be a Disability Income Guarantee of £129 a week for a single person and £169 per couple, with higher rates of allowances for people with disabled children.

He said he was consulting from today on changes to disability benefits including an extra £25 a week in benefit for people who became disabled before they were 20 years old who had little hope of work.

But claimants will have to give evidence of their work prospects.

Mr Darling said: "Our plans will be based on our belief in fairness, will give greatest help to those with the greatest needs, and make sure that benefits only go to those who are entitled to them."

Mr Darling told MPs: "These changes will generate £750 million long-term savings." But real-term spending on disabled people would continue to rise in the long run.

A Welfare Reform Bill is expected in next month's Queen's Speech.