Here’s a transcript. (Each answer is “actually” for the question before last, helpfully put in the same colour, though of course that’s not the joke.)
(Barker plays Magnus Magnusson, the presenter, and Corbett plays a contestant.)
Magnus Magnusson: And so, to our first contender. Good evening, your name please?
Contestant: Uh, good evening.
Magnusson: In the first heat your chosen subject was Answering Questions Before They Were Asked. This time, you have chosen to Answer the Question Before Last each time. Is that correct?
Contestant: Charlie Smithers.
Magnusson: And your time starts…Now! What is palaeontology?
Charlie Smithers: Yes, absolutely correct.
Magnusson: What’s the name of the directory that lists members of the peerage?
Smithers: A study of old fossils.
Magnusson: Correct. Who are Len Murray and Sir Geoffrey Howe?
Smithers: Burke’s. (Berks)
Magnusson: Correct. What is the difference between a donkey and an ass?
Smithers: One’s a trade union leader and the other’s a member of the cabinet.
Magnusson: Correct. Complete the quotation “To be or not to be…”
Smithers: They’re both the same.
Magnusson: Correct. What is Bernard Manning famous for?
Smithers: That is the question.
Magnusson: Correct. Who is the present archbishop of Canterbury?
Smithers: He is a fat man who tells blue jokes.
Magnusson: Correct. What do people kneel on in church?
Smithers: The Right Reverend Robert Runcie.
Magnusson: Correct. What do tarantulas prey on?
Smithers: Hassocks. (?)
Magnusson: Correct. What would you use a rip cord to pull open?
Smithers: Large flies. (flies)
Magnusson: Correct. What sort of a person lived in Bedlam?
Smithers: A parachute. (Parish hoot?)
Magnusson: Correct. What is a jockstrap?
Smithers: A nutcase. (nut case!)
Magnusson: Correct. For what purpose would a decorator use methylene chlorides?
Smithers: A form of athletic support.
Magnusson: Correct. What did Henri de Toulouse-Lautrec do?
Smithers: Paint strippers. (he painted strippers)
Magnusson: Correct. Who is Dean Martin?
Smithers: He’s a kind of artist.
Magnusson: Yes, what sort of artist?
Magnusson: That’s near enough. What make of vehicle is the standard London bus?
Smithers: A Singer.
Magnusson: Correct. In 1892, Brandon Thomas wrote a famous long-running English farce, what was it?
Smithers: British Leyland.
Magnusson: Correct. Complete the following quotation (siren goes) I’ve started so I’ll finish. Complete the following quotation about Mrs. Thatcher: “Her heart may be in the right place but her-“
Smithers: Charley’s Aunt. (Charlies aren’t).