The personal details of 6,500 pensioners have been lost by HM Revenue and Customs in Cardiff.
In the latest data breach to affect the government, a data cartridge went missing after it was sent to HM Revenue and Customs in Cardiff by Preston-based pension firm Countrywide Assured.
The data cartridge, which was sent by courier at the request of HM Revenue and Customs, contained names, addresses, dates of birth, national insurance numbers and pension contribution details.
The cartridge was sent in September and was signed for by HM Revenue and Customs. The loss has come to light as the tax department and the government scramble to carry out an audit of insecure data systems following the loss of 25 million child benefit records.
Earlier this week, it was reported that the Driving Standards Agency in Ireland had lost the details of three million learner drivers.
Countrywide Assured has written letters to those customers affected by the loss - HMRC's seventh major data loss this year. HMRC has informed the Office of the Information Commissioner about the loss.
What the experts say about HMRC's data losses