TENS of thousands of elderly people who received overpayments of pension credit due to Government blunders are to receive a "begging letter'' from ministers asking if they would mind sending the money back voluntarily.

In a partial climbdown, ministers announced that they would be requesting - rather than ordering - repayment from those who benefited through no fault of their own from last year's pounds 130 million pension credit overpayment.

However, many pensioners who received too much because they filled out forms wrongly could still be forced to send money back - although not if this would clearly cause them immediate or obvious "hardship''.

Ministers were forced to try to reassure pensioners yesterday after it was revealed that they would try to "claw back'' as much of the money paid out in error as possible.

On Thursday the Department for Work and Pensions said it would try to get money back where over-payments resulting from Government blunders had been "obvious''.

Organisations representing the elderly accused the Government of being "heartless'' and said it should write off the loss.

David Ruffley, the Conservative spokesman for welfare reform, who uncovered the overpayment figure by asking parliamentary questions, said the Government had failed to ease pensioners' fears.

"There are far too many questions that remain unanswered,'' he said. "Pensioners will be very worried by these letters and many still look certain to face repayment demands as a result of a problem caused by Government incompetence.''

Overpayment of pension credit increased from pounds 50 million in 2003 to pounds 130 million last year - equivalent to 2.1 per cent of total payments. The benefit was introduced in its current form three years ago to help ensure a minimum income for pensioners.