The only Manuel for the job! John Cleese's threat to stop writing Fawlty Towers scripts unless he could sign up Andrew Sachs as beloved clumsy waiter

As Manuel, the hapless Spanish waiter at a certain faded Torquay hotel, Andrew Sachs created such a superb comedy foil that it's impossible to imagine any other actor in the role.

And that's a view Fawlty Towers creator John Cleese originally came to more than 50 years ago, when he was first working on scripts for the now-classic sitcom.

So sure was the Monty Python star that Sachs would make the 'perfect' Manuel, that he threatened to stop writing until the actor signed on the dotted line.

Cleese told The Mail on Sunday: 'I had seen Andrew in Alan Bennett's Habeas Corpus [in London's West End] and realised I had discovered a superb farce performer. 

Obviously, we could have found others, but they would not have been as perfect as Andrew, so I stuck my heels in.'

Documents in the BBC archives reveal executives' concerns that securing Sachs was holding up the scripts, which Cleese was writing with his then-wife Connie Booth, who went on to play chambermaid Polly in the series.

At the time Sachs was trying to make it as a stage actor, and had followed his role in Habeas Corpus with a starring role in the farce No Sex Please We're British.

BBC bosses launched a charm offensive to woo Sachs amid fears for the future of the sitcom.

In a letter to the actor's agent dated February 11, 1975, John Howard Davies, who produced and directed the first series of Fawlty Towers, stressed the need for an answer. 

He added: 'John Cleese is in the position at the moment of postponing the writing of the series as he finds it impossible until the situation about Andrew Sachs is clarified.' 

Three days later Davies wrote again outlining what was at stake. He wrote: 'You know how badly we want Andrew Sachs for the John Cleese series... I have also to try and persuade John Cleese to write the series in the hope of Andrew Sachs being available. However, John Cleese tells me that he likes to write for the actor who is going to play the part.'

The documents, which have been revealed as the show prepares to celebrate its 50th birthday next year, do not give details about Sachs's decision to join the show.

However in a 2014 interview, two years before he died aged 86, Sachs revealed he was worried about being able to do the Spanish accent, and asked Cleese if he could make the waiter German. 

'No! You'd be very good at things if you were German,' the star told him. 'He's got to be Spanish.'

Other letters in the BBC's Written Archives Centre show that Cleese didn't always get his way on casting. 

The pivotal role of Mr Hutchinson in the The Hotel Inspectors episode, eventually played by Bernard Cribbins, was originally offered to The Good Life star Richard Briers.

In a letter dated July 10, 1975, Davies told Briers: 'The part of Hutchinson was written with you in the back of John's mind. I know it is cheeky asking you if you would like to play it, we would love to have you but will quite understand if you don't.'

Two weeks later, Davies offered the same role to Rising Damp star Leonard Rossiter, warning him that Cleese 'plays Basil at high speed'.

Cleese paid tribute to Sachs – while taking a side-swipe at political correctness. He said: 'The key to Manuel's role was that he was always trying his utmost to help, and it was only the language barrier that messed things up.

'Sadly, literal-minded people can only see one interpretation, and it's never one with any humour in it.'