Computer discs holding personal data on 25 million people and 7.2 million families have gone missing, Chancellor Alistair Darling admitted to MPs today.
He said the details included names, addresses, dates of birth, Child Benefit numbers, National Insurance numbers and bank or building society account details.
Paul Gray, chairman of Her Majesty's Revenue and Customs (HMRC), which lost the discs, resigned over the affair today.
The Metropolitan Police have confirmed they are investigating the loss of the password-protected discs which were wrongly sent last month to the National Audit Office (NAO) but never arrived.
Mr Darling said police had no evidence the information "has found its way into the wrong hands" or of any evidence that it has been sued for fraud.
He has appointed Kieran Poynter, chairman of PriceWaterhouse Coopers, to investigate HMRC security procedures.
The Prime Minister has "full confidence" in Mr Darling despite the benefits records blunder, Gordon Brown's spokeswoman said. She added that Mr Darling has not offered to resign.Reuse content