It's been a long time coming, but Leinster hooker Shane Byrnewill get his hands on his Holy Grail this afternoon. He spoke toGerry Thornley

He's lovin' it. Winning a cap in Romania was one thing, but being part of an entire championship and now making his first Six Nations start tops everything. Lately he's come to be known as "Smiler". No one has tried harder or longer for this, and no one has enjoyed it more.

"I just can't help it," he explains. "I've been carrying this smile all through the Six Nations. Playing for Ireland off the bench is great, but I can't describe what this is like. I've always looked at people playing for Ireland with scowls on their faces and I just couldn't understand it. It's the thrill of a lifetime."

It's been his magnificent obsession now for virtually a decade. He broke into the Blackrock team 10 years ago and into the Leinster squad in 1992. He was first called into the Irish squad in 1993 for the tour to Australia, and has been involved every season bar one. Despite pretty much having the Leinster number two jersey stitched to his back for much of the last decade, it's been his misfortune to have been a contemporary of Keith Wood.

Terry Kingston, Allen Clarke, Ross Nesdale and Frankie Sheahan have also been rated ahead of him at various junctures. Even at A level, others have jumped above him in the pecking order, such as Mark McDermott (also a rival at school and club), Billy Mulcahy, Bernard Jackman and, er, Shane McDonald of West Hartlepool. Remember him?

"Guys have always come and gone, and they've come in straight ahead of me. My whole career can be summed up in one word - patience. I just had to wait and I did. I'm so glad I kept going."

Such slights would have downed men of lesser resolve, and he admits there were opportunities to wind down and concentrate more on a successful family enterprise (Arklow Waste Disposal), based in his hometown of Aughrim.

He came close to semi-retirement last season, but changed his mind at the last minute. There was the love of the game, but mostly that elusive first cap, which is also why he turned down a lucrative offer to go to France last summer.

"I didn't want to finish without a cap. I was terrified of letting that happen. That I'd be 40 years of age thinking, 'Jaysus, why didn't I get my hair cut? If I only did that or played this way, I could have done so much more.' I'm so glad it's not going to come to that."

Even when he heard Brian O'Brien read out the team on Tuesday morning, Byrne couldn't believe it. He listened to the replacement list just to make sure, and then had to check with Girvan Dempsey on the team bus what the actual starting 15 was.

"Even playing against New Zealand wouldn't be as good. When you come from one of the home unions, playing in the Six Nations is where it's at," he says. "I'd like to think I would have appreciated it as much way back at the start, but I doubt it. I certainly wouldn't have been getting the support I'm getting now."

Aside from family, friends and well-wishers, Aughrim GAA club, Woodenbridge Golf Club, Dundalk college and Arklow rugby club have all made presentations to him in the last month or so, the latter making him a life-time member. Payback is a pledge to end his playing career with a season or two back there.

Quite why he didn't make the breakthrough sooner is a moot point. He's a good tackler and intelligent mauler, with a high work-rate, and he's also capable of playing a loose, more dynamic game. True, his throwing has been iffy at times - but what hooker's hasn't?

Ultimately, you can't help but feel that he's been judged a little on appearance, namely the long mane down the back of his neck and the slightly unkempt, rotund shape. By comparison to earlier years, Byrne looks in better condition under the current, more professional Leinster regime than ever.

Even his supporters will concede that when he was overlooked in the past, Smiler could be a bit grumpy. He has an argumentative, stubborn streak, and wouldn't be inclined to back down when exchanging views on, say, lineout calls or tactics.

He was never one to respect reputations - witness Keith Wood's return to the Munster fold and Byrne going toe to toe and punch for punch with him. In any event, though now more mature and mellow, Byrne has been regarded as something of a maverick.

Four times he can recall being told to get his hair cut. So why not? "The reason I have always had long hair is because I don't like it short," he says.

To understand Byrne, you probably need to first appreciate his background. Hailing from Aughrim, Gaelic football and athletics were his sports before going to Blackrock College as a boarder. But even there Gaelic remained his first sport until he was 14 or 15. He was then converted into a hooker and Schools Cup medal winner. So there's an unusual mix of smalltown boy and 'Rock boy - and the latter tend not to be the modest or bashful types.

"Maybe it was coming from a small town, I didn't really understand the way the world went round, and to me I was who I was. If somebody came up to me and said just keep doing what you're doing, but just change yourself and everything will happen, I just couldn't understand that.

"I used to just play rugby from the heel of my boots. I used to play instinctively. I had the socks down around my ankles, the hair used to be down around my back, and that was just me playing rugby and enjoying myself. I probably just didn't understand saying 'no' to a request like that."

An independent spirit? "You could use words like independent, but then that kind of leads on to being a rebel, but I wasn't trying to be that, I was just trying to be me."

Nothing in his career came easy, he says. "I was absolutely crap starting off," he says. Then he changed from a tighthead prop to hooker at the behest of school coach Vinny Costello. There were big influences at club level, too, notably Joe McDonald, who helped harden him, and Eddie O'Sullivan, who gave his game more purpose and identity, before Leinster's new-found professionalism kicked in.

A strong Leinster man, to become the province's first centurian - he reckons he's on 93 or 94 appearances now - would be a source of great pride. "We were the great under-achievers," Byrne concedes. "It mimicked the club thing where Blackrock were the great under-achievers as well, but Leinster could never get it to gel. But then Matt (Williams) and Alan Gaffney and the boys came in and tied it together.

"It's a pity we didn't go further in the European Cup, but the Celtic League was the best day with Leinster in 10 years, especially in the style we did it. To lose Matt would be an absolute disaster. The structure now is beyond comparison, and to leave Leinster rudderless again would be chaos."

The combination of a rejuvenated Leinster and Byrne's own buoyant form after making his long-awaited international breakthrough is likely to extend his career by several seasons. "Physically I'm not even near finished. I've plenty of time left in me. I feel stronger now than I've ever done."

Five times he subbed for Ireland prior to the Romanian breakthrough, warming up umpteen times but never coming on in the days before tactical replacements. In '95, while he was injured, Allen Clarke came into the test squad, sat on the bench for Kingston against Fiji and duly came on.

"I remember watching the game with my folks and brother in the Merrion Inn, in fact I think there was a party on, and I remember thinking, 'That is just so typical'. What I felt was so far beyond mere envy.

"Playing for Ireland had become like the Holy Grail. I had been up there but I couldn't get to it. You could maybe say I should have got my chance earlier. But I couldn't have written this script any better."

Only the strong survive.