Half-a-million people are set to lose their disability benefits under Government plans, it has emerged.

Work and Pensions Secretary Iain Duncan Smith said he was determined to introduce radical reforms to disability allowances which could slash the annual cost by £2.24 billion.

Around 500,000 people in the UK who receive disability living allowance (DLA) could no longer be eligible for the replacement personal independence payment (PIP) under the plans, which are outlined in a report by the Department for Work and Pensions this month.

Mr Duncan Smith said there had been a 30% rise in the number of claimants in recent years, with the annual cost of the benefits soon to hit £13bn.

Under the reforms, two million claimants would reassessed in the next four years and only those considered to be in need of support able to qualify.

Mr Duncan Smith said said: "We are creating a new benefit, because the last benefit grew by something like 30% in the past few years. It's been rising well ahead of any other gauge you might make about illness, sickness, disability or general trends in society. A lot of that is down to the way the benefit was structured so that it was very loosely defined. The second thing was that in the assessment, lots of people weren't actually seen.

"The third problem was lifetime awards. Something like 70% had lifetime awards, [which] meant that once they got it you never looked at them again."

Ministers are consulting on the eligibility criteria for the disability benefit system, to be announced in the autumn.