Paddy decided to rob a bank. He got all the gear together - stocking mask, sawn-off shotgun, getaway car and so on - but he realised his accent would mark him out as Irish, so he took elocution lessons for almost a year until he could finally pass as an Englishman.
On the day of the robbery, he donned his mask, rushed into the bank and said, "I say there, I'm terribly sorry but this is a robbery. Be a good chap and fill this sack with lots of lovely lolly."
The cashier said, "you're Irish aren't you?"
Paddy was astonished. "How the divil did ye figure dat out?" he asked.
The cashier replied, "it was easy, you've sawn the wrong end off your shotgun!"