a man, music journalist or TV presenter maybe, is sitting at a desk talking about The Beatles. Seems realistic to begin with but he just keeps talking and talking about The Beatles, going into more mundane detail about them. Just constant talking. Eventually the director yells cut but he keeps talking, then the television studio begins to be dismantled, the part of the set the man is sitting on gets loaded into a truck, driven somewhere else, maybe left in a field somewhere, but the man is still talking non stop about The Beatles and seems completely unaware of where he is and what is going on around him.

Sounds like a Monty Python sketch, it has the same kind of absurdity. Don't think it's Monty Python though but something similar, definitely British, and made in the late 1960s I think.