Tommy is Irish and Bill is English. They go in to a bakery.

Bill whisks three mince pies into his pocket with lightning speed.

The baker doesn't notice.

Bill says to Tommy:-
"You see how clever we English are? You'll never beat that!"

Tommy says:-
"Watch this, an Irishman is always cleverer than an Englishman."

He says to the baker,
"Give me a mince pie, I can show you a magic trick!"

The baker gives him a mince pie which Tommy promptly eats.

Then he says to the baker:
"Give me another mince pie for my magic trick."

The baker is getting suspicious but he gives it to him.  Tommy eats that one too.

Then he says again:
"Give me one more mince pie... "

The baker is getting angry now but gives him one anyway. Tommy eats that one too.

Now the baker is really mad, and he yells:
"And where is your famous magic trick?"

Tommy says:-
"Look in the Englishman's pocket!"