An Englishman, Irishman and a Scotsman are all working as spies
for the UK Government during the cold war when they're captured
by the Ruskies.

Several years pass and the Russian prison starts to get a bit
full, and the oppurtunity arises for an exchange of prisoners.
The Russians talk and decide not to release anyone too high an
IQ and so come up with a simple test in order to decide who they
should release.

Now the cells the three guys are basically pits with high walls
and a door at the top to allow food to be thrown in and/or a
ladder to be lowered. So the Ruskies go along to the Englishmans
cell and shine a torch down to him. "Walk up the beam of light
and you can go free English!"

"**** OFF YOU RUSSIAN BASTARDS! I'M NOT JESUS ****ING CHRIST! I
CAN'T WALK UP A BEAM OF LIGHT!"

The russians leave and go to the Scotsmans cell and shine the
torch down to him. "Walk up the beam of light and you can go
free!"

"OCH! GAN BOIL YE HEID, YA RUSSIAN WANKERS! I CANNY WARK UP NAE
BEAM A FOCKING LIGHT!"

So the russians go to the Irishmans cell and shine the torch
down to him. "Walk up the beam of light and you can go free!"

"YA CAN'T FOOL ME YOU BASTARDS! YOU'LL TURN IT OFF WHEN I'M HALF
WAY UP!"