Porridge, Ronnie Barker and Fletch: the prison sitcom 50 years on

Barker said the scripts written by Clement and La Frenais were “always very, very funny”.

“I would add the odd gag, but it was practically the finished article on the first read-through,” he said.

It wasn’t until the third episode of the first series, A Night In, that Fletcher found himself reluctantly sharing a cell with Lennie Godber, a naïve first-time offender played by Richard Beckinsale.

With Fletcher and Godber sharing most of the screentime, La Frenais said the episode was meant to convey the oppressive feeling of cell doors slamming shut.

He said: “Very early on, we said we’ve got to face the reality of prison. Let’s start off by writing the most restricting episode of all.”

Interviewed in 1976, Beckinsale said: “Dick and Ian decided that it would be a good idea just to write half an hour in one place with just two characters, just to see if it would work.

“That’s where the character came from, just that one exercise of, can we do this, of just having two people in a cell talking to each other.”