If memory is — as it is often described — a “storehouse”, then it is an exceptionally disordered one. Much of its most valuable material is covered in dust and darkness, while small, incidental items tumble out at the merest hint of a fragrance, the sight of a photograph or, especially, the sound of a bar or two of music.

Such thoughts are inspired by my recently having caught a random snatch of Louis Armstrong’s transcendent trumpet solo in Gershwin’s I Was Doing All Right, which in turn, took my mind back to the fabulous Ronnie Scott’s Jazz Club and the fact that the place is 50 years old this year.

Fabulous, at least, is how I remember it 30 years or so ago. If it can still be called fabulous, it will surely be in a very different way. Not only is Louis Armstrong now up there among the celestial trumpets — along with Duke Ellington, Dizzy Gillespie, Roland Kirk and so many of the giants of jazz who graced the club — but Ronnie Scott himself has been dead for 13 years. Jazz, moreover, seems no longer to occupy the place it did in the cultural life of London.

But, all those years ago, Ronnie Scott’s Soho haunt provided one of my most vivid and powerful memories — that of seeing and listening to the incomparable Ella Fitzgerald performing a mere few feet from where I was sitting. It was as if she was in my own living room.

I say this is one of my most vivid memories and yet, in truth, it is vague, almost ethereal. I cannot remember what she was singing, what she said, what she wore, or what day, month, season or year it was. And yet it was overwhelming. We were in the presence not just of someone but of something. Something extraordinary. And it still lights up my murky mental storehouse.

By contrast, my recollection of the landlord and resident tenor sax-player, Ronnie Scott, is undimmed. He and fellow musician Pete King founded the club in 1959, in Gerrard Street. Six years later, it moved round the corner to its present Frith Street address. Like many 1960s jazz joints, the club had quite a Jewish atmosphere (there was even lokshen soup on the menu — is there still?).

Ronnie Scott was wonderfully, engagingly Jewish — in the way defined by another unforgettable entertainer, in another Soho joint, now long defunct.

Lenny Bruce’s anarchic comedy at the Establishment club ignited early 1960s London. His definition of Jewishness will be found in neither dictionary nor halachah. It goes beyond religion, and is not even confined to the human race. A place could be Jewish. New York, for example. “It doesn’t matter even if you’re Catholic,” Bruce famously argued, “if you live in New York, you’re Jewish. If you live in Butte, Montana, you are going to be goyish even if you’re Jewish.”

Elusive it may be, but it seems clear to me that Lenny’s Jew is curious, extrovert, smart, noisy… and funny. Ronnie Scott was all of those things.

He was not religiously observant, despite having been born Ronald Schatt in Tenter Street in the heart of the East End and moving to Stamford Hill, where he was taught the saxophone by Jack Lewis — Vera Lynn’s father-in-law.

Recalling his first jazz group — a quintet including another Jewish guy, Tony Crombie, along with a Scot, an Irishman and an Englishman, Scott once told the JC: “We were going to call ourselves: A Mick and a Jock, Two Yids and a Yok”.

Ronnie Scott’s special Soho cellar was the setting for many an anecdote, some doubtless apocryphal. A friend once told me of being among a small group of guests at the club when Roland Kirk — an astonishing musician who could play two saxophones at once — was doing a session. On seeing Kirk enter, cool and confident in shades, one of my friend’s fellow guests loudly expressed his contempt for anyone “who wears dark glasses indoors”. His host hurriedly whispered to him that Kirk was wearing them because he was blind.

When Roland Kirk finished his set, this mortified individual went up to him, profusely apologised and asked if he could buy him a drink. According to my informant, Kirk then asked the poor, abashed man for an incendiary cocktail of rum, brandy and whisky. At which point, the man exclaimed: “Bloody hell! No wonder you’re f***ing blind!”

Ronnie Scott was well-known for his oft-repeated, mostly downbeat, wisecracks: “You should have been here last Monday. Somebody should have been here — it was so empty, the bouncers were throwing people in.” But first and foremost he was a great jazz figure, responsible for one of the world’s most exciting musical venues — and for my own exciting memory of that New York lady with the lived-in face, whose supremely sweet voice was as warm as a bowl of lokshen soup. In Lenny Bruce’s terms, Ella Fitzgerald, too, was Jewish.

So, olevasholem to Ella, Lenny and, of course, Ronnie. And, to his club, which I am delighted is still going strong under the ownership of the Old Vic’s impresario Sally Greene: a very cool 50th.