This reminds me of a few years ago - an account was opened in my husband's name and �70,000 was deposited. As we were moving house at the time, the letter just got mixed in with our other paperwork.
Then another letter arrived a few months later, advising us of the interest and that the account was about to mature.
We contacted the Halifax and said this was a big mistake and it was'nt ours - they looked into it and sure enough they found the real account holder.
The Halifax sent us a cheque for �25.00 for our inconvenience.
The account was opened at the Halifax in Fenchurch Street, on the same day my husband had been in their to deposit some cheques.
One of those bank workers had made a huge **** up - and if we had'nt reported it - would it ever been found out ????