Computer error destroyed 1m UK tax records | The Register
: "Almost a million taxpayer records were accidently deleted from Inland Revenue computer systems between 1997 and 2000 due to a software problem which went unnoticed for several years.
The Department took three years to discover that software used to cleanse its database of old cases was also wiping live ones from its system.
This resulted in some 364,000 people who cannot be identified being owed £82m, while another 22,000 did not pay tax due of around £6m.
The Revenue admitted the problem last year but the full scale of the error has now only just emerged, following a report from the House of Commons' Public Accounts Committee on 8 September.
A routine housekeeping procedure on the PAYE database, which had been in place for at least 10 years, failed to distinguish between old and live cases, says the report.
The error was revealed when a new management information system was brought in to monitor the software. The Revenue has since introduced a backup system."