ok, this is a bit awkward..
my mate had 1300 GBP too much in his account, if was a CDT (cash deposit trnsaction), but, he didnt do it, and nobody else ahs his number, so its blatently an error on the banks behalf.
its sainsburies bank though, so they dont have a proper cashier like natwest etc. you pay the money in with your paying in book at customer services and they send everything off at the end of the day to the bank (i sumise).
so two months later, its still there, what would you do? confess or withdraw it bit by bit? if it were a proper bank it would br easier to track, but being sainsburies, i aint to sure...