The pensions of tens of thousands of retired NHS, armed services and other public sector staff have been overpaid for decades, the government has said.
About 5% of staff were affected by overpayments worth "tens of millions" of pounds, some made since the 1970s.
Earlier Lib Dem MP Vince Cable asked for assurances bailiffs would not be turning up at ex-servicemen's doors.
Chancellor Alistair Darling said the money need not be repaid but pensions would be adjusted from April 2009.
The issue was raised in the Commons earlier by Mr Cable, the Lib Dem Treasury spokesman, who said he was informed about the problem 10 days ago by a BBC Radio Ulster journalist.
BBC NEWS | Politics | NHS pensions 'overpaid for years'