In comedy, imitation is rightly frowned upon, but adaptation is a seriously under-appreciated art. Imitation is usually equated with laziness, inauthenticity and, indeed, thievery; all one is doing is exploiting someone else's creativity. Adaptation, on the other hand, is quite another matter; it is not only creative in itself, but also a mark of the impact of character upon content.

There is certainly nothing appealing about joke-stealing. The joke thieves are the kind of people whom the philosopher Francis Bacon once likened to ants, because 'they only collect and use'. What they do is unoriginal and dishonest, because they simply repeat what someone else has written or said.

The adaptors, on the other hand, are the sort of people Bacon likened to bees, because the bee 'gathers its material from the flowers of the garden and of the field, but transforms and digests it by a power of its own'. What they do, in the comic world, is take an existing idea, or even a whole routine, and invest so much of their own wit, vision and personality into it that it becomes something that, while still bearing a family resemblance, is now significantly different from the original source material.

This is what tends to be obscured by the understandable anger about the joke thieves. The focus on their blatant borrowings (or, as some stand-ups call it, 'hooverings') has the unfortunate consequence of suggesting that all comedians are either entirely original or unoriginal, purely authors or imitators. The reality, however, is that very little, if anything, which emerges into the comic world is genuinely sui generis, and what passes as new and original is actually, to varying degrees, a fresh take on an existing idea.

What we need to do, therefore, is to stop being quite so obsessed with those who adapt material really badly and brazenly, and start being more appreciative of those who do it really well.

This has long been a common attitude in other branches of the arts. In opera, for example, Mozart, according to recent research, borrowed fairly heavily from The Beneficent Dervish - composed by several players from his inner circle - when he wrote The Magic Flute, while Puccini's Turandot owed its story to the romantic epic Haft Peykar ('Seven Beauties') by the 12th-Century Persian poet Nizami Ganjavi; and, in drama, George Bernard Shaw drew on Tobias Smollett's 1751 novel The Adventures of Peregrine Pickle when writing Pygmalion in 1913, which was in turn quite brilliantly re-imagined by Garson Kanin for his 1946 play Born Yesterday, and Shakespeare, of course, borrowed freely from the likes of Chaucer, Sir Philip Sidney and Plautus.

The same process of adaptation has long been evident in popular culture. John Lennon, for example, famously used a 19th-Century poster for Pablo Fanque's Circus, purchased from an antiques shop in Sevenoaks, to create the 1967 song Being For the Benefit of Mr Kite! ('Everything from the song is from that poster,' he later admitted, 'except the horse wasn't called Henry'). He also, two years later, reversed the arpeggios of Beethoven's Moonlight Sonata to serve as the basis for the comparably compelling Because.

Similarly, though not quite as exhaustively, George Lucas drew heavily on Akira Kurosawa's 1958 film The Hidden Fortress when making Star Wars in 1977, while Christopher Guest followed the formula of Albert Brooks's 1979 movie Real Life when starting his own series of so-called 'mockumentaries'. In yet another medium in 2008, the American street artist Shepard Fairey used Mannie Garcia's photograph of Barack Obama for his stencilled 'Hope' version, which became an iconic contribution of that year's US election campaign.

Whether or not one agrees with Oscar Wilde's contentious qualification - 'Talent borrows, genus steals' - the influences inherent in our inventions have grown increasingly apparent in recent decades. Television has been eating and regurgitating itself for ages, music is sampling its past to the point of self-parody, and in Hollywood it's now Groundhog Day even for Groundhog Day.

This brings us back to comedy. Thanks to the unprecedented amount of old comic material in easy access via the Internet - the audio, the video, the transcripts and the quotes - it's never been harder not to be influenced subliminally, let alone consciously, by existing ideas, themes and routines. The very evanescence of the experience - a quick glance at a tweet, for example, followed by another unrelated distraction - means that, although it is simpler than ever to search for the original authorship of something, there is less inclination to bother.

That is why, for example, the shamelessly lazy shoehorning-in of a very old joke about Diana Dors (the mayor of her home town, being so anxious not to mispronounce her real surname of Fluck, ends up introducing her as 'Diana Clunt') in 2019 on the first episode of This Time With Alan Partridge ('And here's Alice Clunt'. 'It's Alice Fluck, actually'. 'Ah yes, I see what I've done'), was greeted by many on social media, and in newspapers, as if an ingenious new gag had just been heard.

The provenance, though never irrelevant, arguably matters rather less, however, when the appropriation leads to the genuine craft of adaptation. Some performers do not just lift material; they liberate it from a lesser form.

A case in point is Sir Billy Connolly. It was while I was 'ghost-editing' (or, as I believe the more fashionable phrase now puts it, 'ghost-curating') his recent collection of comic material, Tall Tales And Wee Stories, that I became aware of just how well-evolved his skills of adaptation had become over the course of his long career. It is, indeed, hard to think of anyone better at planting a personal flag in someone else's material ('Connollising'?) and gradually cultivating it into something fresh and fertile.

In the early days of his career, there was indeed a fairly 'normal' amount of basic 'hoovering' going on, as he looked for ideas from practically anywhere and everywhere. In his first TV special in 1976, for example, there was a veritable procession of very old club gags parroted for public approval (e.g. straight repeats: 'There was this Irish guy who bought two hundred acres of land - the tide was oot'; and slight revisions: 'What about the two Laplanders doing the crossword? One says to the other, "Oh, Michael, I've got a hard one here". He says, "What's that?" He says, "It's got four letters, and old MacDonald had one". He says. "I've got it - it's a farm!" The other one says, "Ah, yes, of course". He says, "How do you spell that?" The other one says, "I think it's e-i-e-i-o"').

By his own admission, he also took a joke from a musician friend of his called Tam Quinn ('Jesus's apostles were eating a Chinese takeaway when Jesus came in. Jesus asked them, "Where did you get that?" and they said, "Oh, Judas bought it. He seems to have come into some money"'), told it that night during his set, and immediately got a positive reception. In the next few months, as a consequence, he would build on it until it became his early classic, the 'Crucifixion' routine.

Even his celebrated breakthrough gag on Parkinson, in 1975, about the half-buried bum that served as a parking space for a bike, had been in circulation for ages up and down the northern pubs and clubs. His distinctiveness in using it there was simply in being the first one to believe, unlike so many other comics of the time, that he could get away with telling it on a mainstream TV show.

Even later on in his career, there would still be the odd act of somewhat crude appropriation, such as the line that was 'borrowed' from the 1976 TV special, The Barry Humphries Show, which featured Edna Everage in Stratford-upon-Avon (spying a passing Morris Traveller, the housewife but not quite yet a superstar exclaimed, 'Oh, look, there's a little half-timbered car. I love those, I call them Tudor cars!'); this turned up again in a fine 1991 Billy Connolly routine about Scottish women and scones ('They've all got Morris Minor Travellers, with the wood - it's a sort of Tudor estate car!'). He also clearly leaned quite heavily on Richard Pryor's material from the late 1970s when developing his 'Shouting at Wildebeest' routine a couple of decades later; he was indebted to George Carlin's material in the 1996 show Back In Town, from which he picked and mixed to develop his own variations on the dangers of 'beigism'; and dipped into Dave Allen's later riffs on language, commercialism and the nature of ageing to engage with the same range of themes.

Most of the time, however, as a mature comic performer, he could reformulate a specific joke or story, reanimate it from within, and the 'Connollisation' would be complete. Take, for example, the very basic joke that, of all people, Bernard Manning had been telling since (at least) the late 1960s:

In the early 1980s, Sir Billy 'revived' it, but also adapted it, to turn it into this routine:

Another unlikely influence was an anecdote - probably apocryphal - much-used by British comics, often on chat shows from the 1990s onwards, about Freddie Starr. The standard version was as follows:

Sir Billy developed this into a 2010 routine called (informally) 'The Push':

Such comparisons as these do not merely highlight the structural simplicity of the essential gags but, more importantly, illustrate just how thoroughly, imaginatively and intimately Connolly could create something significantly richer, more distinct and superior (what the critic Walter Benjamin called 'narrative amplitude'), not only in his own voice but also via his own inimitable comic vision.

The Starr and Manning manipulations, however, were relatively modest by Sir Billy's high standards. There are other instances of adoption and adaptation that really show the full extent of his ability to take a common seed and grow something that feels unique.

In 1970, for example, Peter Sellers told a short comic story - which he attributed to Michael Caine but had in fact already been in circulation for several years - about alcohol and the Pope:

The Sellers version was very much like all of the previous, very basic, versions, except that he tweaked it superficially to suit his distinctive gift for comic accents. As a brilliant interpreter of other people's scripts, it was typically well-judged in its self-limitation, and added just enough charm to work as a revision that was worthwhile.

The Sellers version, however, soon faded from most people's memory, to the extent that when Sir Billy seized on the source later on in the same decade, he stamped his own signature so surely on to the material that it struck the majority of his audience as a completely new routine:

That is the kind of adaptation to admire. The comparison reveals the inventiveness of the adaptor rather than merely, or mainly, his initial source material.

It takes the same basic set-up, and the same basic pay-off, that Sellers himself had borrowed, but, once deconstructed and reconstructed, it reappears bearing the syntax, the structure and the soul of Sir Billy Connolly. It is, as always, not the comic material that is unique, but rather the comic spirit that lives and breathes and plays around within it.

Knowing about such adaptations, therefore, far from diminishing one's respect and admiration for this remarkable performer - this most busy of Baconian bees - surely ought to increase it, because the insight allows us to appreciate more fully the exceptional cleverness of his craft. The same basic stories can pass out of the mouths of many different storytellers before finding the one with the magic to make them really come alive and remain in the mind. No one, in British comedy, has been a better teller, and re-teller, of tales than Sir Billy Connolly.