Masters of the performing arts can frustrate and infuriate as expertly as they reward. Why isn't Woody Allen content to make us laugh anymore? Why did Van Morrison insist on trying even harder to wreck his reputation by performing Astral Weeks on stage last year, given that for the past two decades he hasn't sung a note with anything remotely resembling feeling? How on earth did anyone ever believe, for a micro-instant, that remaking The Ladykillers - let alone making Psycho II or Superman III in the first place - was a bright idea? Among English cricket lovers, none of those querulous questions is quite so persistent as the one that has been flummoxing us since the last Caribbean tour: what makes Steve Harmison tick?

Infuriating cricketers do not spring all that readily to mind. Most are acutely aware of their limitations and adapt accordingly. These days, because we see them in action so often, rather than having them confined to scorecards and rose-tinted typing, we know those limitations too, or fancy that we do, and adjust our demands and expectations accordingly. We, the audience, appreciate their humanity, empathise with their fallibility. Those demands and expectations, though, can make and break those who elect to perform before audiences bigger than a bedroom mirror and are asked to represent a nation, region or community; to those we perceive, enviously, as unfairly blessed, the demands can be overwhelming, the expectations crippling. They certainly broke Graeme Hick.

The young Tom Graveney exasperated many; ditto David Gower; but that was down to a toxic potion of ingratitude and class warfare. Sachin Tendulkar did, until he finally made a match-winning fourth-innings hundred. But infuriate? Shahid Afridi undoubtedly. Talent minus application equals waste. Ditto Dwayne Smith and possibly Marlon Samuels, though both still have time to atone. Jacques Kallis? Maybe, given the magnificence of his technique, but at least the numbers justify the means. Andrew Flintoff? Perhaps: his batting has never kicked on as it should have, though redemption may yet be possible. From where I'm sitting, if we accept that Afridi's triumphs have come as a consequence of his excesses rather than in spite of them, that leaves Harmison in a league of his very own.

THE TERRAIN has been ploughed so often. In physical terms, for someone who earns his corn running quite fast and projecting something a good deal faster, Harmison lacks for nothing, even allowing for the few extra pounds he is currently carrying. Not since prime-time Curtly Ambrose has anyone wrought quite so much havoc with sheer bounce. Few, moreover, are capable of unleashing a more lethal yorker. Few world-beating fast bowlers, conversely, have seemed quite so gentle, so self-effacing, so… un-fastbowlerish. Granted, as Justin Langer and Ricky Ponting discovered at Lord's four years ago, he has a capacity for inflicting pain, but that doesn't mean he enjoys doing so. Granted, there was that unworthy dismissal of Inzamam-ul-Haq in late 2005, when Pakistan's captain pushed the ball back only to be adjudged run out as he sought to take cover from a vicious return throw, but hindsight confirms that as a profoundly atypical aberration. All this we know. But still.

It would be crass in the extreme to whinge that Harmison has gone downhill ever since he last rumbled in on Courtney Walsh's old stomping-ground. Lest we ever allow him to forget it, that opening episode of the 2004 Wisden Trophy series witnessed "Harmy" as we've never glimpsed him, before or since. Everything was aligned and in sync as he shot down the home order for 47, abetted by a septet of slips and gullies, to finish with 7 for 12: the cheapest seven-fer in Test annals. It was as if, Mike Selvey so memorably observed in the Guardian, "the bodysnatchers had invaded him with Ambrose's spirit". You have to go back to 1896, to George Lohmann's 8 for 7 against South Africa in Port Elizabeth, to find the only bowler who has ever taken that many wickets in a Test innings at such paltry average cost. After that, there's pretty much nowhere else to go but down.

Nevertheless, since those salad days of 2004 (67 wickets at 23.92, strike-rate a Marshallesque 47.1 balls per, No.1 in the world rankings) the returns have been diminishing alarmingly, inexorably: 46 victims at 34.86 in 2005, followed by 33 at 38.06, 24 at 35.66 and, last year, six at 57.33 and at a strike-rate of 91. The sum of those mediocre parts is 109 wickets in 34 Tests: certainly not disgraceful, but still, for those who demand that he deliver throat balls and swerving full-lengthers with a vestige of consistency, nowhere near tolerable. Even selectors, coaches and captains, who merely entreat and implore, must be disappointed. The decision to award him another central contract remains a contentious show of faith.

Then again, maybe that's how it works with him. Maybe the diagnosis is textbook. He cannot handle expectation. The unconfident seldom can, and Harmison is not half as self-assured as many imagine he should be. As Mike Atherton put it so eloquently in the Times, he gives the impression "of being someone who is intimidated by his own talent".

When we met in 2005, on the eve of that momentous Ashes series, he exuded self-awareness. "I'm laidback," he said. "Don't get phased too much or riled or upset." He knew what made him special - "Not many can do what I do - bowl 90mph consistently. Name me one." Never driven by cricket - his dream was to play for Newcastle United; the first Test he saw was his debut - he also appeared to have an unusually firm handle on the whole status thing: "Never been one to say it's the be-all and end-all, never obsessed by it. If it all went tomorrow, so be it." The musings of someone anxious not to put pressure on himself, to minimise even his own expectations? That's how it struck me. Those who expressed surprise earlier this week when he revealed that he never watches videos of his finest hours would have been less so had they heard the following: "I always forget about what I've done in the previous game when the next one comes along. It's the next ball that counts." Keep on keeping on; never look back.

Similarly instructive was his column in the Daily Mail last August, shortly after his good friend Michael Vaughan had tendered his tearful resignation, midway through Kevin Pietersen's first Test as his successor:

"On the day before the match, Kevin walked over to me and said simply: 'I want you in my team. You'll be taking the new ball,' and it felt like he had injected me with a syringe full of confidence. By the time he sent text messages to all of us that night to wish us luck and remind all of us to enjoy it, I was so pumped up I texted back that I felt like a kid on Christmas Eve."

At first the remedy appeared to work. That Oval match saw some inspired spells, a Test-best 49 and victory. Then came India and a swift return to mediocrity, albeit, he has since admitted, while carrying an injury. Now, after a fleeting appearance as Dr Feelgood, Pietersen is back in the chorus line. It remains to be seen whether Andrew Strauss' syringe is more effective.

THE FIGURES, the bare bones, still comprise a CV to envy: 217 Test wickets, 10th among Poms; more five-fers than Maurice Tate; a better strike-rate than John Snow; a better average than his bosom buddy Flintoff. Among Poms, only Atherton, Ian Botham, Graham Gooch, Kevin Pietersen, Stewart and Thorpe have claimed more than his five Man-of-the-Match awards; none was an out-and-out bowler and only Botham (12 in 102 Tests, one every eight-and-a-half outings) hauled in the individual cheques with greater alacrity than Harmison (just under one every dozen). Harmison also remains the only Pommie bowler to top the ICC Test chart. Yet what lingers is that palpable sense of unfulfilment.

But is that entirely fair? Such are the strains of bowling fast - let alone doing so with an action that demands more oiling than a supertanker - and such is the apparent lack of inner drive, it is a wonder he's achieved this much. More to the point, that suspicion of being short-changed explains why selectors continue to curse every twanged hamstring or bruised fetlock. It's the promise of Harmison that obsesses them, the fear that the team loses menace when he's not there. And they know the opposition almost invariably think exactly the same. No bowler since Botham has traded so profitably on his reputation. It's a bit like having a nuclear warhead: you don't necessarily need to fire it; you need it as a deterrent.

Of course, no article about the man whose tabloid soubriquet will never be "The Northumbrian Nasty" would be complete without reference to that notorious and utterly unabashed preference for family and hearth. Yes, he has been known to sulk and mooch about on tour. Yes, his wicket-count, average and strike-rate overseas (89, 36.60 and 69.6 in 29 Tests) are all vastly inferior to those on terra familiar (128, 28.28 and 51.4 in 30). Yes, last Wednesday the Daily Mail's Paul Newman did observe: "At times Harmison looks so world weary and feels that everybody is against him." But his willingness to listen when Pietersen sought, successfully, to lure him back into the one-day arena was encouraging. Besides, if he is so averse to leaving his wife and four children, why return to India after the Mumbai atrocities? Nobody appears to have twisted his arm (though Pietersen may well have had a go). Granted, the letters "I", "P" and "L" might have entered the equation, but would his desire for a slice of the pie really have been thwarted had he stayed at home? Unlike Andy Caddick seven winters ago, he must have known, with Australians looming, that he would almost certainly have been forgiven. And unlike Caddick, he attracts a protective, tolerant fondness.

For Strauss, the auguries aren't bad. After all, he was in charge at friendly, bouncy Old Trafford in 2006 when Harmison snapped up both Pakistan openers in his first three overs, sent back Inzamam with the most unplayable snorter imaginable, took 6 for 19 and wound up with 11 for 76 all told as England romped by an innings and plenty. Trouble is, pitches that suitable don't crop up that often (all the more reason to lament Old Trafford's absence from the Ashes itinerary). Which is why, when they do, as they probably will in Kingston, omitting him is folly.

As ever, there was a defensive, at times plaintive, tone to his pre-Test musings. He insists he always tries his "nuts off", that he loves playing for his country, but "people don't seem to understand that". Then again, when it comes to the mechanics of his job, self-understanding has always seemed in short supply. "I just can't put my finger on it," he confessed, helplessly. "Sometimes it clicks and sometimes it doesn't."

So what can Strauss do to get Harmison pumped up and fizzing down those 93mph yorkers? Appeal to his pride by accusing him of wasting his talents? Can't see that working. All the indications are that he responds to carrots, not sticks. Tell him he could still be "t' finest ruddy fast bowler who ever drew breath" (c. FS Trueman)? Much shrewder. Fly Alan Shearer in for a pep talk? Why not? Ask the Barmy Army to sing "The Blaydon Races"? It couldn't hurt. Whatever it takes. Secret weapons must be handled with care. Sadly, Harmison has appeared too keen to keep himself concealed, the better to suppress expectation.

There is another way of looking at it. A notoriously slow starter in Test series, Harmison needs to be firmly in the groove before he can mix it with the best and give of his best. Which is why he came back so well against South Africa late last summer - he'd been the chief reason Durham were about to win their maiden Championship - and why he laboured so fruitlessly in India, injury notwithstanding. The difference between his output in the first Test of a series and the second is not insignificant: 63 wickets at 30 to 68 at 25. And as rubbers wear on, that average declines still further - 39 in third Tests, 36 in fourth and 41 in fifth.

No less obvious, as Peter Moores doubtless alighted upon, is the chasm separating his performances in the first and second innings of a game: when England bat first Harmison averages 41.80; field first and it's 25.79. In the 15 victories that ensued, his contribution has been priceless: 91 wickets at 19.32, strike-rate 40.6, six of his eight five-fers and that Manchester 10-fer. And before you ask, 105 of his 137 wickets (at 25.84) in the games in which England have fielded first, including that 7 for 12, have come when the toss has been lost. The answer? Pick him exclusively for the first two games - they usually decide the overall outcome anyway - then ensure you take the opposition captain out for a crafty pre-toss pint and convince him that batting first is his only option. Not so much a horse for a course, then, as a horse for a circumstance.

THE BOTTOM LINE, for now, is that we're back at Sabina, his field of dreams. Relaunch pads don't come much more propitious than this, not least since the mainsprings of the current West Indies order - Chris Gayle, Ramnaresh Sarwan and Shivnarine Chanderpaul - are carrying scars from 2004. Besides, Gayle (seven dismissals in 12 Tests) and Sarwan (six in 10) just happen to be Harmison's most willing bunnies. If omens of that ilk don't raise that reluctant dander, one strongly suspects that nothing will.

Then again, he might like to consider a comment from the Channel 9 box last week (I can't be sure whether it was Ian Healy, Bill Lawry or Michael Slater, but I'm absolutely positive it wasn't Mark Nicholas). In the wake of a lavish wide, it was suggested, gigglingly, that the perpetrator had done "a Harmy".

Is that how you want them to remember you Down Under, Steve? Thought not.