The Serious Fraud Office (SFO) were fined £180,000 after thousands of private documents from a notable bribery investigation were erroneously sent to the wrong person.
There were papers from an investigation into BAE Systems deal; they comprised of evidence relating to 64 people. The Information Commissioner's Office states that the information were feebly sent to a witness in the case in a startling blunder.
The SFO said it had "substantially overhauled its procedures".
The leaked documents included bank statements, hospital invoices and passport details related to the SFO's investigation into allegations that executives at BAE received payments as part of an arms deal with Saudi Arabia.
Accusations of corruption and bribery led to an SFO probe in 2004, however, it was closed in 2006 on grounds of public interest, over concerns that relations with Saudi Arabia were being marred.
After the case closed, the SFO sent more than 2,000 bags of evidence to the witness between November 2011 and February 2013.
This is the first time that the SFO were fined by the UK's privacy regulator.