The Blackmail show is a favourite Monty Python sketch from the second series (Episode 18, transmitted 1970).

In it, Michael Palin plays a smarmy television game show host who extorts money from the viewers by threatening to reveal embarrassing or illegal facts about viewers:

And to start tonight's show, let's see our first contestant, all the way from Manchester, on the big screen please: MRS. BETTY TEAL! (shows a picture of Mrs. Teal with a black censor bar on her eyes) Hello, Mrs. Teal, lovely to have you on the show. Now Mrs. Teal, if you're looking in tonight, this is for 15 pounds: and is to stop us from revealing the name of your LOVER IN BOLTON!! So, Mrs. Teal, send us 15 pounds, by return of post please, and your husband Trevor, and your lovely children Diane, Janice, and Juliet, need never know the name... of your LOVER IN BOLTON!

And now: a letter, a hotel registration book, and a series of photographs, which could add up to divorce, premature retirement, and possible criminal proceedings for a company director in Bromsgrove. He's a freemason, and a Conservative M.P., so that's 3,000 pounds please Mr. S... thank you... to stop us from revealing:

Your name,

the name of the three other people involved,

the youth organization to which they belonged,

and the shop where you bought the equipment!

It then cuts to a photograph of two sets of bare feet. One pair appears to be those of an adult male. The other pair, standing opposite and yet very close to the adult's, appear to be those of a much younger male. Palin announces over the picture, "We'll be seeing more of that photo later on in the programme.... unless we hear from Charles or Michael..."

But right now, yes, everyone, it's the moment you've all been waiting for; it's time for our Stop the Film spot! As you know, the rules are very simple. We have taken a film which contains compromising scenes and unpleasant details which could wreck a man's career. But, the victim may 'phone me at any moment, and stop the film. But remember, the money increases as the film goes on, so-o-o-o: the longer you leave it, the *more* you have to pay! Tonight, Stop the Film visits the little Thames-side village of Thames Ditton.

As the blurry film plays out (it's of an upper class man visiting a dominatrix), a digital display shows a rapidly increasing number of pounds which abruptly stops when a telephone rings. The camera cuts to Palin who is seen saying, "...no sir, we don't morally censure you, we just want the money."

The caller is instructed to send the money to:

Blackmail

Behind The Hot Water Pipes

Third Washroom Along

Victoria Station