For those who aren't up to scratch on their mid-century English comics, Benny Hill was born in 1924, and epitomises a certain kind of British vaudeville seaside comedy - slapstick, innuendo-filled, and now desperately unfashionable. (Re-runs of The Benny Hill Show ran in the US on cable TV stations for years after he fell out of fashion in the UK.)
The song in question, "Ernie (The Fastest Milkman In The West)," tells the comic tale of milkman Ernie struggling (and ultimately failing) to win the affections of a young window.
The opening verse - which Cameron quoted on Thursday night - goes as follows:
You could hear the hoof beats pound as they raced across the ground,
And the clatter of the wheels as they spun 'round and 'round.
And he galloped into market street, his badge upon his chest,
His name was Ernie, and he drove the fastest milk cart in the west.
And here's the TV version of it, innuendos and all:
"Ernie" was originally written in 1950, but didn't enjoy its first TV release until 1970. At the time, Cameron was the tender age of 4, and living at the family home in Berkshire. The following year it was released as a single - it was a smash hit, and was the 1971 Christmas number 1.
"I just remember playing this at home, over and over again."
Ernie is also, Cameron revealed, "the only song whose words I can remember." He even recites some of the words on Desert Island Discs - you can listen to the entire show here (Cameron discusses the song from the 7:30-mark onwards):
"Wonderful, universal themes," the Conservative party leader remarks after the song finishes playing. "I haven't heard it in ages that that was ... that was ... bliss."
(He hastily writes off its more suggestive sections as an "early love song.")
Yesterday, the Prime Minister said that though he's not much of a singer, he does sometimes sing "Ernie" in the shower. But his passion for Benny Hill isn't relegated to his personal life.
It's a strange fascination for Cameron. The Prime Minister is often criticised for being out-of-touch - Eton-educated, descended from aristocracy, and very well off. In contrast, Benny Hill's crude, slapstick comedy was unapologetic in its proletarian appeal.