What should I do with a huge cheque?

As a soft toy wholesaler we constantly receive emails which vaguely offer to buy huge amounts of stock off us without being too specific about what they want. Invariably it must be shipped outside of Europe. I am sure you get similar things and i presume you do what we do which is delete them and move on

So how about this as a situation. Customer from abroad orders a nice amount of stock and says payment will follow. A week later we receive an anguished email to say that 10 times the amount of the bill has been deposited can we help. I laugh and write the whole order off as an attempt to con us in some way (I hadn't shipped the goods hence the good humour. The criminal Simon Osbourne has taught me that much!)

But one day later the bank rings to say they have infact received a cheque for over £20,000. On closer inspection it has been written out incorrectly and its actually for more than £200,000

So i email the customer and say i have received his cheque, we will not cash it but what does he want me to do with it. Silence. No answer. Its been 2 weeks and i have a cheque for almost quarter of a million pounds sitting on my desk

Any suggestions as to whether its a scam, how it works and what should i do with the cheque!

7th Nov - the customer has emailed us again! He has obviously forgotten that hes tried it on with us before and is trying to place another order. Can't wait to see how much the cheque is going to be for this time! Any bets?