It seems at least a year old and is reported on some many websites that it is impossible (or rather very tedious) to figure out where it originated.

BBC NEWS | Talk about Newsnight | Friday, 19 October, 2007

And finally Newsnight viewer Chris Mills sent in this Joke fit for an eleven year old:
"The knock on from the recent US sub prime market problems, that hit Northern Rock among others, shows no signs of letting up. In fact it has now badly affected the banking system in Japan. In the last 7 days the Origami Bank has folded, Sumo Bank has gone belly up and Bonsai Bank plans to cutback some of its branches....."

and so on