He's a pretty cool customer Harry Williams. Win, lose, or draw, he doesn't rant or rave in the dressingroom, nor does his generally composed, easy-going, good-humoured demeanour change much either. As one of his Ulster players puts it: "He's the same all the time, he pisses ice cubes".

Even in the midst of a defeat earlier this season in Connacht, the first he had experienced in his fifth interprovincial campaign as an Ulster coach, he wore it endearingly well. "I don't like it," he maintained, but he was smiling as he said it, and on his way to join a group of old friends in the beer tent for some convivial post-match natter. Could this really be a professional coach?

It's easy to presume he was the same convivial figure moments before in the losers' dressingroom. You certainly couldn't picture him in a fly-on-the-wall documentary unleashing a dressingroom tirade of high-pitched expletives complete with bleeps every second. As it transpires though, there's method in his deliberate nonmadness.

"Somebody once said to me, and this is not original, that `anatomically there is 12 inches between a pat on the back and a kick up the arse. Which would you rather have?' That was said to me a long, long time ago.

"Once you start screaming and yelling, you lose your reason, you lose your logic, you stop thinking, and it's a case of getting rid of your own frustration rather than trying to be clinical with the players. So when I lose my temper it's something serious."

The guard did come down once this year, after the initial meeting with Toulouse in France when Ulster lost 39-3. Williams was, by his own admission, "really, really furious" and regrets it. "It made me feel better, but it didn't do a hell of a lot for anybody else."

In keeping with the low-key, low-profile approach, Williams has a more evolved coaching style than most, allowing a significant input from the players. "He listens to us, which is great, and if it's a good point, he takes it on board," says one.

Not everything fell into place at the outset. After four games without a win, at the behest of the full-timers, Ulster's working day was tailored to their needs rather than the part-timers, and Ulster's season was turned around at a stroke last October. They've won seven games on the trot since.

Despite his benign dictatorship, Williams is described as "the key" by his captain David Humphreys. The coach has cleverly masked deficiencies in the scrums and potential defensive weaknesses out wide, so that they've hardly counted. He identified the Stade Francais midfield as a potential weak link, in that they were below-average distributors, and so Ulster closed them down quickly and decisively, thereby stymying any designs on taking on Ulster out wide at source.

Team spirit comes with winning of course (when do you ever hear of a split dressingroom in a winning environment?). Williams says the camaraderie is strong, and it's as much by accident as design, then things become really easy for the coach. But it also comes from the modus operandi of the coach/manager. Harry clearly has something.

Born and reared in Belfast, he went to school in Sullivan Upper, and from there he played rugby at Kings Scholars, a famous nursery, while studying to become a teacher. Williams then taught in the `Big Boys' school' in Belfast while playing briefly for Malone. After marrying June he put down roots in Bangor, as a teacher at Bangor Grammar School.

He taught in the prep department, and taught PE and games in the senior school, while playing prop for Bangor until his playing career ceased in 1977. Of the latter, he laughs and says: "It was about average. Put it this way I achieved greater heights as a coach than I did as a player." Having coached the school first team, the progression into senior coaching was easier and more likely.

He had two stints as coach, covering seven years of an eight-year period, during a fertile Cup and League spell for Bangor, before graduating to Ulster coach after a year's break in 1987. In four interprovincial campaigns, Ulster never lost a match.

"I think there were 20 internationals through the team in that period, guys who were internationals or who were to become internationals," Williams points out, as if he was merely the orchestrator.

Another year out followed - Williams believes "it refreshes the soul" - before he assumed the Irish A coaching position for three years. "A difficult one that. That's probably as difficult a one as I've done," he recalls.

"It was a case of once the senior side was selected then the A side was selected - quite naturally the needs were for the senior side. There wasn't a lot of time to work with them."

Another year out, another coaching job. This time it was Bective Rangers. Down in Donnybrook, Williams is still very well liked. They talk of him as a good coach who didn't have an awful lot to work with.

"As a Division Two side they had as much talent as anybody else," he says tactfully. "When I went to Bective I was never under any illusions that I was going to have 10 internationals in the team. I was aware that coming back to the club scene there would be difficulties."

One of those was his job as a headmaster in Hollywood Primary and the subsequent need to commute from Belfast.

A recent day trip to Dublin made him wonder how on earth he kept that going for a season and a half, though it was probably the prime reason for him quitting the job at Bective.

"But I must admit Bective was very good for me. When you're working with the really elite players, the guys like Humphreys and so on, you're coaching at a different level. When you're coaching a club side, you're right back to the nitty gritty; the very basics of organisation. Whereas at international or interpro rugby, part of that is innate. Everybody can play their part, whereas with a club side - and I'm not speaking of Bective specifically - there are times when you have to devise tactical plans to cover up places where there are serious deficiencies."

Williams thus faced life without involvement in rugby, though as it transpired, only for a month. "Then just by sheer fluke, I was approached about the Ulster job," he says. That was January 1998. Bidding adieu to teaching was a relief. Williams stresses that he was fortunate with his school "and I have no regrets about any of my schools. But the actual job is terrible."

Why? "No matter what is done, it's never enough. No matter what society's ills are, it's always stuck to the schools to try and cure. You're basically in a no-win situation."

Williams has two children of his own. His son Keith lives in Scotland, working in the insurance industry, and daughter Amanda has a home in Bangor as well. Ask him what the future holds for him, and he says: "Wait till you hear this one, after the game on Saturday, my first priority is to grout my daughter's kitchen floor. I promised her at Easter and it's still not grouted."

Despite the extension to Ulster's season - their final pool game was almost three months ago - and the intensity of the last few weeks, you sense Williams is enjoying his job and the quality of his life more than he has done in some time.

Winning helps. "Oh yes. There have been a lot of enjoyable years, but this has certainly been by far the most rewarding. Being full-time, you've time to plan and think. "It's great when you can get a bunch of players and weld them together, and there's no disharmony or back chat, yet they're all prepared to contribute as well. That's been the strength, we have a system where the players are invited to contributed. Some times they're good and some times they're not."

His coaching philosophy: "That I'm the boss, but to be the boss you don't have to be rude, or crude, or arrogant to other people. I look on these guys as my surrogate sons and I try to treat them as intelligent, grown men. And you don't treat intelligent grown men badly by shouting at them. There's no need to be abusive. So my idea is to try and draw the best out of players. If you can talk to them on an even keel, cajole them, push them etc I don't see any reason why people need to fall out with each other over it."

Comparisons are odious, and a bit futile when this team is placed against Williams's class of '87 to '90. "That team was already well established, so they had their own brand of charisma and their own way of doing things, and mine was a tinkering role. This team has been completely different. We've created a team this time."

The sense of job satisfaction then is even greater now and all the more so if the team ensure themselves of sporting immortality by winning today.

"We've tried to emphasise the importance of this, and the chance that the players have to make history. No other Irish team can do what we've done. We are the first to reach the final of the European Cup and we want to be the first team to win it for Ireland. It's not just for us. Although we're a very tight-knit bunch, we're very aware that this is not just for Ulster, this is for Ireland."

And for Harry Williams too.