It came from Viz aicmfp

( broadsword now that's fresh, Tue 13 Apr 2010, 11:27, 2 replies)

Its ancient
and was about in the middle of the last century.

A person would walk around various seaside resorts, and if you went upto him carrying a certain daily newspaper, and said "you are such and such, and I claim my five pounds." You got the money.
( Bartleby A dead man on vacation, Tue 13 Apr 2010, 11:41, closed)

It actually started in the sun.
I think the character was Chalky White who would appear on a city's streets accompanied by buxom wenches. The idea was you would approach him and say "You are Chalky White and I claim my five pounds." If correct you received your moolah.

It is now used as a comedy device to indicate an ironic assessment of someone's nature or a reflection of their behaviour by simile.

Mindpiss. Love the use of last century though. Gives it gravitas.
(porkylips looks better as the sun goes down., Tue 13 Apr 2010, 11:42, closed)

Close, it was the Westminster Gazette and the character was Lobby Lud
en.wikipedia.org/wiki/Lobby_Lud
( Michael Ellis contributes nothing, Tue 13 Apr 2010, 11:51, closed)