There were three gents at a bar in Oxford Street.
The Englishman proudly boasted he could drink twenty "screwdrivers" and still stand on his head.
The Irishman claimed he could drink twenty whiskeys and still sing "O Danny Boy" note perfect.
The Arab said he couldn't do either of these. At that he let rip with a tremendous fart.
"Now there's enough gas to light this whole room" he proclaimed.
"Good one" said the Irishman "we always knew you were full of shit".