Her Majesty's Revenue and Customs is offering a reward of £20,000 for information leading to the recovery of the lost child benefit data discs.
The discs, with information on 25m people, were lost in mid-November en route from a child benefit office in Sunderland to the National Audit Office.
Estimates of the potential value of the discs to identity thieves and other crooks vary widely, but all are well north of £20,000. The Liberal Democrat acting leader Vince Cable reckoned on £60 per record giving a total value of £1.5bn.
The Metropolitan Police investigation has now been reduced - 47 detectives were involved in early searches, but this has fallen to 32. Police have been searching for the missing data since 18 November.
The Met said the search had been particularly difficult due to how common computer discs are and the number and size of offices which needed searching. Computers were forensically examined to verify witness accounts.
The statement said: "The main searches have concluded and we are now extending to areas that require searches or enquiries to be made in order to rule them out. However, indications suggest that these locations are less likely to have been a transit route for the parcel than the areas already searched."
The offer of £20,000 is primarily aimed at encouraging HMRC, Child Benefit, National Audit Office and Treasury staff to look for the discs, but is open to anyone. Staff were told that finding the discs and handing them to their union representative or line manager would not amount to a criminal offence. The discs are marked TCO and were contained in CD cases within a Jiffy bag that was inside a yellow envelope. The envelope was addressed to the NAO on Buckingham Palace Road, London. ®