He's big, he's strong, he has a prodigious left boot, he hits the line well, he has good hands and he bears the hallmark of all good players in any team game: he always seems to have time. Yet two weeks after turning 29, Ciaran Clarke wins only his fourth cap today and his first in five years. Something's not right here.

Has Ciaran Clarke fulfilled his potential? As an opening gambit to an interview it mightn't seem the friendliest, but Clarke (or "Peanuts" as he's known within the game) is such a friendly and easy-going fellow that he smiles readily and admits: "Possibly not, no."

"Why have I only got three? Lots of reasons. Loss of form I'll start with, because if I say anything else I'll just be making excuses. Or at least form on and off, not loss of form. Injuries. Other people as in other players. I mean, me not playing well and other guys playing better. I'd imagine that's pretty much it."

So there you have it. It's straightforward enough really. Yet when you watch Clarke on a good day you'd wonder why he hasn't a bucketload of caps. True, he has the odd defensive lapse, and he can be a bit slow on the turn, although one of the first words that come to mind about Clarke is "solid". Nor would he have that acceleration, that kick of, say, Kevin Nowlan. But he's an innate footballer, and when confident there's little he can't do.

Philip Danaher has a theory that most Irish players, unless they're a Brendan Mullin, have to go through the treadmill of being dropped and knocked, before coming back better, stronger, more experienced players.

Certainly, Clarke strikes you as being older and wiser. His longtime team-mate at Terenure, Paul Hennebry, reckons Clarke is "a much, much more mature player now than he was three or four years ago.

"He's far more secure in defence. He reads the game well and is beginning to dictate from the back. He controls the back three. He's a good, all-round solid player and he's still deadly when he hits the line. He never takes the tackle or goes to ground and loses the ball, and I haven't seen him drop a ball in a year and a half. And he still has a horse of a left foot."

Hennebry says that Clarke simply hasn't been used properly, although there have been the odd days when Clarke seems to just go walkabout. So the inconsistent form, which he candidly puts forward as the primary reason for a relatively unfulfilled potential, seems the most interesting aspect of the Clarke conundrum.

"I don't know why. Sometimes it's through non-consistency as regards injuries and things; sometimes through psyche, sometimes through any amount of things I suppose."

He quickly refutes any theory that he might lack a bit of oomph. "It's been tough over the last while with a different job, but I was training professionally before it was professional. I was always fairly diligent in my training. Whether it's thought about me on the pitch or not, I wouldn't have thought so."

The thing that strikes you most about Clarke on the pitch, and was particularly so even amid the frenzy of his international debut against France at Lansdowne Road in 1993, is that he never seems unduly flustered or hurried.

He went on to score a drop goal in the game against Wales. "Actually it's really weird because any time I think about it I look at it from the point of view of watching it on the telly and not from being there. Nothing much. Brads (Michael Bradley) threw me the ball and there was myself and Simon Geoghegan and a lot more Welsh people so it was kind of a last option."

Then came the "high" of the 173 win over England: "the whole day, the atmosphere, completely dominating the game, everything. Fifteen mad Irishmen kicking lumps. Someone came up with the idea of physically turning to the crowd and getting them to scream at us, from start to finish, every chance we got. And it really worked." He also hit the line on the short side in the build-up to Mick Galwey's famous, matchwinning try. "I was actually on the ground after being hit by Brian Moore and Brads picked it up. But that was the seal."

The only video nasty of that campaign, and every Saturday thereafter, was of Ieuan Evans rounding Clarke during the opening credits to the Grandstand theme tune. "There's Ciaran Clarke disappearing out of the side of the picture," he laughs.

Yet, while his form since may have oscillated occasionally at `A', Leinster or less rarely Terenure level, truly one can say Clarke has never let Ireland down. His failure to add to those three caps in the intervening five years is a cause of some mystery to his many admirers within the game. Form and injuries aside, selectorial whims may also have been a factor, although he's too much of a diplomat to say so.

"You take nothing for granted," he reasons, phlegmatically. "I just hoped and thought that maybe I would but then going on that development tour (to Zimbabwe and Namibia in '93) - I went away and did okay, and Conor (O'Shea) did better. I don't remember playing particularly badly on that tour. But he was dead keen and maybe I wasn't so keen on the tour."

Ah, O'Shea. No discussion of one is complete without mention of the other. Their paths seem destined to forever cross over. On arrival at the Castletroy Hotel on Sunday evening, a tired but beaming Clarke was immediately congratulated at the front door by Rob Henderson and Mark McCall. He hadn't stepped five yards inside the foyer, when Warren Gatland handed him a phone. It was the injured O'Shea on the other end of the line.

They are good mates despite the rivalry. In what must be a unique case, both players were picked on both the development tours of '93 and '97. When they linked up for the latter in Limerick last summer they just nodded and laughed, as if to say: so we meet again.

As was mentioned here a couple of weeks ago, O'Shea and Clarke were not school rivals at Terenure College as legend would have it. They were a year apart, almost a different lifetime by schools' standards, besides which O'Shea was an out-half until converting at SCT.

Clarke describes himself as "a crap Junior B centre" before moving to full-back in his senior years. He returned from injury at the expense of O'Shea for the semi-final and final of his last school year - losing to Blackrock (room-mate this week Victor Costello, Stephen McIvor and co) in the decider. He would lose to Blackrock in the McCorry Cup (under-19s) final at club level as well, not to mention more Leinster Cup finals and big games with his only club Terenure, than he cares to remember.

There was no representative recognition. Indeed, where others climbed the ladder of schools, under-21s and A levels, Clarke just hopped onto the top rung against France five years ago. "I never represented Ireland at any other level before that. I mean, I got my first A cap after I got my first full international cap."

Hennebry draws similarities between Danaher, the young fullback, and Clarke, and many people have felt that Clarke himself had the requisite requirements to convert to centre.

"A lot of people have said it to me over the years," says Clarke, anticipating the question, before adding almost wearily: "I just don't want to play there. I've been playing full-back for so long now and I think I'm a better full-back than I would ever be a centre.

"I like the whole position. There's a good bit of running, there's a good bit of ball. Okay you stand under high balls and that, but you take the rough with the smooth."

The rough, more often than not, has come in the shape of injuries. Injury disrupted Clarke's '93-'94 season, and O'Shea was first in the full-back line to play Romania, since when he's occasionally sat on the bench as O'Shea's understudy or else watched O'Shea or Jim Staples from afar. Two years ago Clarke tore his cruciate ligament in his right knee.

Thus, his excellent free-scoring form of last season went largely unnoticed beyond the All-Ireland League and any hopes of an international return appeared to have been well and truly scuppered when Mike Ruddock dropped him from the Leinster team.

You sense that Clarke doesn't feel he got a fair crack of the whip from the Leinster management. Yet he doesn't want to re-open old sores and one of the many to ring and congratulate him on Monday night was Ruddock.

His off-field responsibilities have grown in recent years. Married to Emma in August 1995, it is fair to say that Clarke's job as a pharmaceutical rep with Pinewood Helpcare since November 1996 has placed greater demands on his time away from the game. The Leinster episode, when reportedly late for training, suggested that maybe Clarke was the amateur of old caught in the modern professional game.

Yet Clarke has always been regarded as a diligent trainer, and Hennebry states that: "no-one deserves it more, because I see the guy train. He still does his donkey work. It used to be himself and Hogey (Niall Hogan) but now, even with Hogey gone, you'll see Clarkey slogging away afterwards."

He looked genuinely sharp in training on Monday, and far from fazed by his recall to more rarefied surrounds. Well respected by his peers, he mixes effortlessly and probably wouldn't have an enemy in the game.

"He's very focussed. He's not vocal and he's not a headbanger in the dressing-room," says Hennebry. "He's a very solid, relaxed, easy-going, committed fella. He's the type of guy people would like as a friend. He wouldn't be a problem except in the Leinster Branch."

His recall from the "wilderness" has earned him the moniker "Grissly Adams" in the Irish squad this week although he's still universally known as "Peanuts", a derivative family nickname in line with elder brothers Sean ("coconuts") and Brendan ("Nuts").

Clarke reckons his "15 minutes of fame in `83 only lasted about six weeks. It was all over then." But he's been through the Irish rugby treadmill and survived. He won't let Ireland down and maybe this 15 minutes will turn into something a bit more enduring.