The Serious Fraud Office says it has accidentally sent thousands of pages of evidence relating to an investigation into defence giant BAE Systems to the wrong person.
A statement from the office said it identified the data loss in May and that 98 percent of the material has already been recovered.
The office said that none of the material related to matters of national security.
More top news
More than 50 dog surfers of all breeds and sizes joined an annual dog surfing competition in California
A painting by artist LS Lowry is to go on show to the public for the first time.
A third of Olympic and world championships medals have been won by athletes with allegedly suspicious doping test results, report claims