GOVERNMENT changes to the benefits system have caused such widespread confusion that tens of thousands of Britain's poorest pensioners were missing out on about £1,000 a year in unclaimed benefits, it was claimed today.

Up to 770,000 of the two million households entitled to the Minimum Income Guarantee do not claim and each is missing out on an average £22 a week, a report by the National Audit Office found.

The figures were published as a second report, by Age Concern, claimed that around half of all pensioners were surviving on an inadequate income.

The NAO report criticised the Department for Work and Pensions for not doing more to encourage pensioners to claim their full entitlement.

Government figures show the problem could be worse than when Labour came to power in 1997.

Then up to 760,000 pensioners were thought to be missing out, a figure which increased to 870,000 in 1997-8.

That dropped to 670,000 in 1998-99 but increased again to 770,000 in 1999-2000.