The Cabinet Office has been fined £500,000 for publishing the postal addresses of more than 1,000 New Year Honour recipients online.
The accidental disclosure included the private address of Elton John, Tory MP Iain Duncan Smith, and the former director of public prosecutions, Alison Saunders.
The data remained online for two hours and 21 minutes – and was accessed more than 3,800 times.