For many years there was a Jimmy Anderson poster on the back of London buses advertising a well-known brand of bro-vitamins, the kind of everyday pill that makes men happy, toned, slabbed, thickly coiffured, good at sport, magnetic in social situations and frankly – if I can speak plainly here – stone cold model-handsome. The advert seems to have gone now which is a shame because it was very funny. What made it work was the strapline “I FEEL FANTASTIC”, pasted in throbbing alpha-dog script over a picture of Anderson staring balefully into the camera, looking chiselled and fit as ever, but wearing that familiar expression of a man marooned at a windswept rural bus stop in a pair of rain sodden plimsolls who has, just this moment, taken his first ever bite of celery.

It was never really clear if Anderson was supposed to be saying I feel fantastic, which just doesn’t seem like the kind of thing that would happen, or overhearing someone else saying it and muttering and rolling his eyes, or if this was always intended as a highly sophisticated piece of double-take branding, like hiring Mark E Smith to scoot around in a Mini covered in stickers trying to sell you a portered new-build two-bed in Fulham.

The real reason it seems timely now is that Anderson’s longevity, his basic refusal to yield, has passed from a useful tool for selling vitamins into something genuinely startling. Cricket loves its milestones. Here’s another one, a marker that really does deserve its own flag. Anderson, England’s greatest ever wicket-taker, currently the sixth-ranked men’s Test bowler in the world, turns 40 on Saturday.

Yes! Forty! Anderson hates talking about his age. He says it’s irrelevant, which is true, but also not true once you take a step back and absorb how much of an outlier he has become. By the time the first Test against South Africa rolls around in mid-August England will have, for the first time ever, a 40-year-old opening bowler – and not some creaking old sage, but this miraculously lithe figure still snaking in and sending down the odd 87mph delivery, surely the oldest person ever to bowl at these speeds in an international game.

Frankly the whole thing is fantastical, a feat of will and athletic brilliance that, as has often been the case with Anderson, feels as though it really does have to mean something. But what exactly? There is a tendency in English sport to overdo the fond fuzzy eulogy stuff. A few weeks back Ben Stokes retired from a format he has played 10 times in the past three years, games nobody can remember, which are literally just coloured shirts doing things, a mumbled speech in front of a TV board, and was hailed like a viking king being sent off in his flaming longboat watched by the spirits of the noble warrior dead. The English are good at this. We do send-offs and speeches. Three cheers. Ladies and gentleman, the Queen. It’s a kind of status brag, subtly pitched. This is different though. Trying to work out what Anderson means. This has been a constant refrain since his emergence as a skunk-haired prodigy through to his enthronement as an indestructible embodiment of high summer craft.

The search for meaning usually centres on greatness. It’s the easiest thing.

Look at the numbers. When Anderson got to 600 wickets two years ago he was hailed by some, in this country at least, as the greatest fast bowler of all time. But it is pretty hard to be the greatest. Malcolm Marshall, Dale Steyn, Wasim Akram, Curtly Ambrose, Pat Cummins, Richard Hadlee and Glenn McGrath all say hi. Eighteen pace bowlers have taken more than 200 wickets and averaged under 25 in the modern era, and Anderson is not one of them.

Jimmy Anderson acknowledges the crowd
Jimmy Anderson acknowledges the crowd after taking his fifth wicket against Pakistan at Trent Bridge in 2010. Since that summer he has taken over 500 Test wickets at an average of around 23. Photograph: Philip Brown/Reuters

On the other hand Anderson’s body of work is such a vast data mine it isn’t hard to find outright greatness in there. The summer of 2010 is a Damascene moment in Anderson lore. Already 28 years old, scarred by injury and failure, Anderson was moved to trust his basic action, to focus on pressure and craft. Since then he has more than 500 wickets at around 23, evidence of absolute mastery of his skills, the ability to swing, wobble, reverse, bowl dry, to be more effective in the last three years overseas than in England. This is greatness, unarguable and hard-earned.But, it isn’t just that. Because people also love Anderson. There is something so fond and tender in his presence on an English field. Even the run-up feels intimate, with that reluctant first step, then a kind of shiver as he eases up into a sprint, feet splayed into the coil and whip, head still dipping like a maestro’s bow at the point of release. Anderson has sent down 68,970 deliveries this way, has run the length of Britain, with a ball in his hand.

It feels significant too that he emerged outside the current closed world of age group systems and elite pathways, that his first incarnation was as an unskilled teenage tearaway, driven by the outsider’s curiosity to study and evolve and learn new forms. This is in part why people love Anderson. But it’s not just that either. Perhaps it’s about beauty, because if he does have claim on ultimacy it is this, that Anderson is the most aesthetically beautiful of all seam and swing bowlers. Even now there is something beguiling in the ease and grace of his movements, in the variations of wrist and fingertips.

My own favourite bit of Anderson is still his five-fer on Test debut as a baggy-trousered kid, where he keeps on turning the Zimbabwe batters around the wrong way, making them chase ghosts, clipping to leg, then whirling back as off-stump clanks out of the ground, a street magician’s trick. Over time it became clear that he is basically English cricket’s Warne, all deception and control, but a Warne designed for cold days and cold fingers, softer English air.

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And perhaps this is what Anderson means, if he means anything. Never mind the numbers, the beauty, the backstory. What he represents is a state of grace. There he is, still out there doing this thing in the dog days of a dying form. Let’s face it, one reason Anderson can do this is because only England really zeroes on Test cricket to this degree, because in the end the rest of the world has its eyes elsewhere.

Another summer of Anderson: it is a kind of fever dream, with the promise that while he’s still running in we can pretend that this will always happen, that things will always feel fantastical, the last great silent movie actor cleaning up before the talkies wash all this away. There are many different reasons why. But we really will never see his like again.