The Foreign and Commonwealth Office (FCO) lost the details of 188 people this year, in five separate incidents.
Its annual resource accounts show 70 people's names, addresses, dates of birth and family details were lost from an "inadequately protected PC from outside secured government premises" in September last year.
In May 2007, details of around 50 people were made public after "unauthorised disclosure by a contractor". An independent investigator's report was submitted to Parliament as a result.
In November 2007, details of 50,000 visa applicants were on view to visitors to a website run by the FCO. The incident was investigated by the Information Commissioner's Office and the FCO signed a formal undertaking to comply with the principles of the Data Protection Act. This incident was not included in the FCO's report.
The FCO said in its report, "The Department will continue to monitor and assess its information risks, in light of the events noted above, in order to identify and address any weaknesses and ensure continuous improvement of its systems".