It's usually the Home Office that leads the way in the British government's eternal Olympics of stupidity; but now and again, someone is inspired to go that bit further, to be a tiger, to raise the bar.
Having built a monster centralised database of every last child in the UK, the Revenue burned it to a pair of disks and sent them off with a courier...and never saw 'em again. With no less than 25 million records compromised including names, addresses, National Insurance numbers, and bank accounts, this must be the world champion securifart.
"Dear Sir, The Department for Work and Pensions requires you to update your bank details now or face losing out on child benefit for your" (son/daughter) ($name)...
We told them it would happen, and they went ahead and did it.