I think it was early 1960s.

Ooh, ice cream has been made with (sound disparaging) vegetable fat.

Now (delighted) they are going to have dairy ice cream.

Samples of each A and B on four plates, four food critics or restaurant owners or the like.

Tasting test. Which is the dairy?

Two say one, two say the other.

The two who (purportedly) got it right asked about it.

Oh, yes, can tell the difference etc etc

Almost end of programme.

"Oh, I've just been told the samples were muddled up, it was the other way round."

End of programme.

-----

Another programme.

A panel discuusion about something.

People introduced, but for the medical man, professional rules, they can't mention his name.

Discussion.

"As Dr Name_said_out_loud was saying ... etc" (approximate quote)

----

Another medical one, name can't be mentioned.

Interviewer asks detailed question.

"Oh, we've run out of time" (approximate quote as best remembered)

So the medical man had been got there and not said a word.

----

One from the 1950s I think.

Panorama.

"Well we were going to talk about defence policy this evening but as there is now going to be a debate in Parliament on defence policy within the next fourteen days we are not allowed to do so" (approximate quote)

https://api.parliament.uk/historic-hans … 4-day-rule

William