By Matthew Legg, Business Editor

Last updated 09:32, Friday, 29 August 2008

Pensioners could miss out on hundreds of pounds worth of backdated benefits as a result of rule changes that come into force later this year.

Claim and counter-claim: The Government says its new wider benefits package will not leave pensioners out of pocket overall, but it is thought that some of the UK’s poorest pensioners may lose out on backdated claims

From October 6, people applying for pension credit, housing benefit or council tax benefit will only be able to have their claims backdated for three months, rather than a year as is currently the case.

It is thought that around 100,000 of the UK’s poorest pensioners could be affected by the changes, with people potentially losing out on up to £2,000.

The move is part of a shake-up by the Government which aims to boost the number of people claiming means-tested benefits by making it easier for people to apply for them. From October 6, people will be able to claim the pension credit, council tax benefit and housing benefit through a single phone call without having to fill in a form.

The £100m that the Government estimates it will save through limiting the backdated payments will be used to pay for this reform, with money also going towards increasing the pension credit and winter fuel payment.

The Department for Work and Pensions defended the move saying 70 per cent of people claiming backdated benefits claimed them for three months or less.

But Government figures show that around 110,000 pensioners still claim arrears for more than three months, while 70,000 make backdated claims for the whole year.

The average backdated claim in 2006/07 was for £700, but people could claim up to £2,000 in certain cases.

Pensions Minister Mike O’Brien said: “Many pensioners are still not claiming benefits they may be entitled to. That’s why we are urging pensioners who may be eligible to claim and making the process as easy as possible.

“The change will not affect existing customers and new customers can still claim 12 months backdating if they apply before October 6.

“The changes are part of a wider package of measures to make claiming benefits simpler and more automatic and increase take-up.”

Mervyn Kohler, special adviser at Help the Aged, said: “I think on balance this represents a good package. It is a trade-off worth having.”

He said if people lost a £1,000 windfall through not having the pension credit backdated for a year, they were likely to gain around the same amount through automatically receiving council tax benefit.

But he said the group was urging pensioners to submit claims for pension credit before Monday October 6 so that they could benefit from the full 12 months backdating.