Who’d have thought, 50 years ago, I’d be sitting here writing a blog about what is still the greatest TV comedy sketch ever? That’s my opinion, of course, and nothing divides opinion quite like comedy.

There are plenty of lists of the greatest ever sketches and the results differ wildly (especially depending on whether the lists or polls are of British or American origin), and recent hits sometimes usurp the greats (Little Britain’s Lou and Andy topped the Channel 4 poll), but there are certain classics which feature quite regularly. The Dead Parrot, the One-Legged Tarzan and Two Soups usually make an appearance, as well as a much-loved routine by the Two Ronnies – you know the one. But in my humble estimation, the Ronnies couldn’t hold a candle to the sketch that would top my list – in fact they couldn’t hold FOUR candles to it. That sketch was first broadcast exactly 50 years ago tonight, on the 31st October 1967, though it has become such a classic that it has been performed by different casts on different occasions down the years and is regularly wrongly associated with a different show to the one it premiered in.

The Four Yorkshiremen sketch first appeared as the last item of the 6th edition of the second series of At Last the 1948 Show, written and performed by John Cleese, Graham Chapman, Tim Brooke-Taylor and Marty Feldman. The show featured sketches by members of the quartet, linked by a hostess – “the lovely” Aimi MacDonald. The final sketch of each show usually featured all four writer/performers. Which of them actually wrote the Four Yorkshiremen sketch was long a matter of dispute, though it seems that Tim came up with the original concept and he was given a credit of thanks for it on the recent Monty Python re-union shows.

But what makes this sketch so special? Of course, it is hilariously funny and the performances are brilliant, but what else? What makes it such a great experience, no matter how many times you have seen it? And why is this, original performance so much better than the ones which followed? For a start it is beautifully structured – almost musical. I would compare it to a string quartet playing a series of variations, like the second movement of Schubert’s Death and the Maiden quartet. It starts with a few short comments which gradually lengthen into these wonderful exaggerated reminiscences which are repeated in style and elaborated in content as they are passed around the four performers, each echoing and then outdoing the previous contributor. The four are actually seated like a string quartet – Cleese at first violin, Brooke-Taylor as second, Chapman on viola and Feldman as ‘cello. And the script is just so poetic, full of alliteration and echoes: “But it were ‘ouse to us”; “Corridor? We used to dream of livin’ in a corridor”. The direction by Ian Fordyce is brilliant too, full of close-ups and two shots and cut to the rhythm established by the script. Above all, the performances by all four are perfectly timed and judged.

The thing that has made this sketch seem such a classic is the fact that it has been re-performed many times, with different casts, usually as part of live theatre shows, particularly charity galas. it’s first stage outings were as part of Monty Python Live shows, first at Drury Lane (recorded in audio only), then at the Hollywood Bowl, which was filmed. Strangely, Cleese was not involved in that performance – Eric Idle taking his part. Chapman played the same role as he did in the original, with Michael Palin filling in for Brooke-Taylor and Terry Jones for Feldman. And so began the association with Monty Python’s Flying Circus which persists to this day, and it is regularly referred to as a Python sketch. Other performances followed in such events as The Secret Policeman’s Ball and Comic Relief, as well as the most recent Python re-union shows at the O2 referred to earlier, though none have come close to rivalling the perfection of the original, probably because the need to declaim in a theatre ruins the essential rhythm of the piece. Guest performers have included Rowan Atkinson and a revival for Amnesty in 2001 featuring Eddie Izzard, Harry Enfield, Vic Reeves and Alan Rickman was more of a parody than a performance. More recently, the Four Fundraisers sketch for Comic Relief starred Izzard, John Bishop, David Walliams and Davina McCall trying to outdo each other with their tales of the remarkable things they had done for charity (of course, the sketch is introduced with the Monty Python theme!). You can see them all on YouTube, together with countless amateur versions and even one in Hungarian! (hopefully not a misleading translation).

And the Four Yorkshiremen was not the only 1948 Show sketch re-cycled in other shows. One even turned up in Monty Python’s Fliegende Zirkus (the show the Pythons did for German TV), while Marty Feldman revived the wonderful Bookshop Sketch and a few others in his own show, Marty, for the BBC. Cleese and Atkinson also performed a version of the Beekeeper sketch on stage.

But there’s another major reason why the stage performances usurped the original and the association with Python was cemented – the recording of the 1948 Show in question, along with most of the other editions, was lost for many years. In addition, the show had only been seen in its complete form in the ITV London (Rediffusion) area. Fortunately, that was where I lived and, being a massive devotee of TV comedy in the sixties, I never missed it (I also bought the album of sketches from the first series and bored people by reciting them word-for-word at any opportunity). When I joined the BFI archive in 1988, one of the first things I did was search the Rediffusion collection, which the archive had acquired, for copies of the show and was disappointed to find only two had survived. Then, in 1990, Dick Fiddy, my friend and colleague at the BFI, told me he had heard rumours that there were some copies of the show in Sweden. So, at that year’s gathering of the International Federation of Television Archives I approached Sten and Lasse from SVT and asked them if they had any knowledge of this. “Oh, yes”, they replied, “we have them. We bring them out every Christmas for a laugh”. They promised to send me copies and confirmed that they had five shows, but when they arrived they turned out to be compilations of sketches from both series, edited together for international distribution, rather than original programmes. The Four Yorkshiremen sketch, however, was there and we showed it at the National Film Theatre. Shortly after that, Dick, Veronica Taylor and myself founded the BFI’s Missing, Believed Wiped campaign to search for lost British TV shows and At Last the 1948 Show has been one of the great successes. Copies of the shows have come back from private collectors, from overseas (ABC Australia) and from the archive of David Frost (who was Executive Producer). There are now only three of the 13 shows which are incomplete, and the search goes on for those.

And the existence of the telerecordings allows a long-overdue re-evaluation of the show itself, which until now has been seen mainly as just a pre-cursor to Monty Python’s Flying Circus, but deserves recognition as a true classic in its own right. Python was more formally innovative and had the greater impact, but the 1948 Show is more consistently funny across its 13 editions. John Cleese, Tim Brooke-Taylor and Aimi MacDonald have all enthusiastically joined in the screenings of the recovered shows and Cleese notes in his autobiography, So, Anyway (Random House, 2014) that he was delighted and surprised at just how good the material was when he got to see it again. The 1948 Show also beat Python to the use of a well-known phrase now indelibly associated with the latter: the words “and now for something completely different” were first spoken by Aimi MacDonald in one of her links between the sketches.

So, please join me in raising a passable glass of Chateau de Chasselas in honour of the 50th anniversary of the Four Yorkshiremen – undoubtedly the greatest TV comedy sketch of all time. But try telling Two Ronnies or Little Britain fans that – will they believe you?