The moniker "Caesar" doesn't reveal too much about Conor O'Shea, save for a passing resemblance and a once dodgy hair cut at a time when he played for Ireland in the Students World Cup in Italy. The preceding nickname of "Mustard" (i.e. keen as opposed to gas) says an awful lot more.

Here's a player who has taken to the professional ranks as if to the manor born. Disciplined and thorough in his preparation, a believer in the work ethic, O'Shea thinks about the game deeply and is always working on making the most of his talent. He was known as mustard long before professionalism, whereas now he has both the time and the money.

Different strokes for different folks. Where others find the professional routine of eating, sleeping and drinking rugby monotonous, O'Shea takes care of his diet and when he's not playing is usually sleeping.

"For any person who plays sports it's their dream; to play it and to be paid," he says, chuckling at the sheer simplicity of it. "I started off and I wasn't playing it for any money, and I still would play it for no money. I probably wouldn't put in the same amount of time because it's now my job. But I'd certainly be putting it in on the nights like I always did at the start.

"You know, it's an exciting time to be involved in it. There are a lot of ups and downs, and I suppose it's a learning experience for life. But it's something I could never have dreamt of and I'm enjoying every second of it."

The slightly starry-eyed youngster is still inside him. As a kid he looked up in awe at internationals and thought to himself "God, I could never get there, those guys are so good."

"Now you kind of pinch yourself and say like; `I'm here now - I can't believe it'. To actually get there you just have to put in so much hard work. I mean, I feel I've come up against people with plenty more talent than I have, who maybe wouldn't put in as much work. And that's all part of it. It's just trying to maximise every last inch of talent that you have. Once you can do that you can't look back and regret anything. You play it for fun, you play it for enjoyment, but you play to get every last ounce out of yourself."

Such self-effacement is almost a surprise. Good-humoured, bright and a ready chatter, in passing you'd almost think him cocky. But in talking to him at length, you realise he would actually hate being seen in that light, and in truth O'Shea is more self-assured than arrogant.

All of this tallies with an arduous enough route to the top.

Actually, O'Shea's supposed secondary role to Ciaran Clarke at school is a bit of a misnomer. It's true that Clarke returned from injury to replace O'Shea on the school's Senior Cup team for the Leinster semi-finals, but that was the only season their paths crossed. Two years younger, O'Shea still had another SCT season left in him.

Less known is the fact that O'Shea was originally an out-half, and was in the same class as, and half-back partner to, Niall Hogan from the age of eight up. "And then I moved back to full-back to collect his pass," jokes O'Shea. In fact, he's a huge fan. "I'm biased but with Hogey he'll give you 150 per cent."

Even though O'Shea went to Lansdowne, the O'Shea-Clarke thing carried on regardless - all the while with Leinster and then, bizarrely, on both the development tours of 1993 and 1997. It got so they'd just nod and laugh on renewing acquaintances and rivalry.

"I think it happens with anyone who plays in the same position. You tend to know them very well. Yes, there's rivalry but it's a friendly rivalry. We both helped each other and possibly spurred each other one."

O'Shea went to UCD after school (making the Leinster under-19s) and then joined Lansdowne, not to avoid Clarke. His father had strong links there, Moss Keane was a family friend and, typically, "a change of environment is always good for you." Seven "absolutely fabulous" years at Lansdowne nurtures the hope that he might one day return.

By the time another change in environment with London Irish proved too irresistible before the start of last season, O'Shea had begun to make the breakthrough. An impressive substitute's appearance in the 1992 final trial was undermined by a broken ankle, but that was the making of him in some ways.

The frustration of missing out for six months spurred him on to an even greater workload before the 1993 development tour. "The frustration of having missed out on a possible cap at the time in that championship actually drove me to the point of insanity.

That's really when I could say I never trained as hard in my life. It was on that tour that I got the mustardy thing, because I'd never leave the training pitch. I just felt I'd missed out on something and there was going to be no stoned unturned to try and get back."

The inevitable first cap came against Romania in the autumn of 1993. He still cites it as the best day of his life and can vividly remember the day he was told. "You always hear people saying `where were you when man landed on the moon?' or whatever. Things like that happen and they pass me by. I was stopped in a train station in Portarlington, coming back with Leinster from a game against Munster in Musgrave Park. That's when I heard I was picked," he recalls with a loud laugh.

All told, 17 caps have been steadily accumulated. Again there was a rivalry with Jim Staples, who O'Shea may have had in mind when talking about more innately talented players. "We had a kind of a tit for tat all the way up to last season. Jim is a great character and a good guy to learn off. He taught me how to conduct myself off the field and how to relax. Even in London now when we meet, we still get on great. You see it in a lot of positions. Scrumhalves always hang around together."

O'Shea originally debunked to London to do a masters in sports science and then to a sports academy in America for a year. "Last year I worked while playing with London Irish to try and actually get some appliance to the academia that you learnt, which is always chicken and egg."

He still does some consultancy work, and along with David Humphreys and Niall Woods O'Shea is taking French lessons. Oops.

But there's no time for his golfing passion or such like. When not obsessively keeping in touch with his family and friends back in Dublin, then he spends much of his time resting or sleeping.

He's now with his third international coach at Sunbury, beginning with Clive Woodward. "Clive is very open-minded about the game and probably took off blinkers that were previously there. I don't think there's anything that he would be afraid to try."

It helped that Irish were roaring through the second division and to the semi-finals of the Cup. "Willie then did a magnificent job in keeping us up last year. I think that the affinity that the players built up with him was immense. To a lot of the guys he was a lot more than just a coach. And it was a huge wrench to see him go to be honest."

Anderson's loyalty doesn't prevent him rating some of his former players as low as 10th, 11th or 12th out of the dozen English Premiership players in their respective positions. But O'Shea he puts at "one or two".

O'Shea earned a reputation for one lapse in concentration per match, he may not have the slickest pass in the world and his sidestep may be of the Maori variety. But as straight runners go he's one of the best. To see him take a steepling Paul Hull garryowen two weeks ago with a 20 yard sprint and leap, before cutting through a swathe of Bristolians and instinctively putting Niall Woods clear with a reverse pass on half-way, took the breath away.

Modestly, he would like to improve "everything - I would retire tomorrow if I played the perfect game. I'd love to say I'll be Christian Cullen and Serge Blanco rolled into one, but I know I never will be. I just want to be the best I ever can be."

Playing confidently and scoring regularly in a losing London Irish side this season O'Shea has become a bit like the team's Alan Shearer. Get your money on O'Shea to score the first try is the word within the camp at Sunbury, where the on-course bookie rather foolishly offered the full-back at 9/1 last week.

"Yeah, the old bookies have me down the odds for the try-scoring stakes and I think a few people are having a flutter on me and making the odd bit of money."

Last week's try constituted his 16th of an injury disrupted season, but once more was no more than minor consolation in a 41-7 defeat.

"Yeah, I'm getting in," he sighs wearily, "but to be totally honest I'd swap them for winning a lot more matches.

"It's an old cliche but it's the team that counts," says O'Shea, and admittedly this is their captain talking. "Yeah it's been going well individually and it has been going well for a few players individually but collectively the results haven't been coming. And really you play a game to win. That's when you get your full enjoyment out of it."

This is a common enough theme from London Irish this season, where so many players have been reportedly having good seasons yet results indicate otherwise. In reality, their squad was until recently practically the same as the one which struggled to survive last season. They don't match up well in the pack to others in the English Premiership and although when they're good, they're very, very good, when they're bad they're truly horrid.

Like last week, against a Wasps side they had thrillingly beaten in the league earlier in the season. This was possibly the nadir of their season, and may simply have been an inevitable fall-out to the removal of Willie Anderson and the general mood within the club.

O'Shea is at a loss to explain it, though his remedy is typically straightforward. "We'll have to keep on putting in the hard work. People will be cynical and say they're getting beaten week-in and week-out, but the only way we can put that right is by keeping on working and turning it around."

The same applies to Ireland. O'Shea realises people are sick of hearing about learning curves or turning corners. "I've said to myself that I'm refusing to say that. People will only believe when they see the hard evidence. So what's the point in me sitting here and saying: `we're doing this right or we're doing that right'?"

He still awaits his first Irish try. He's still kicking himself for not dummying Rowen Shepherd instead of offloading to Mark McCall a fortnight ago. Through all the gloom though O'Shea still believes there is plenty to be positive about, if the nucleus of a young squad can stay together. "We'll go through lean times but I suppose to taste the sweet you taste the pain."

The outlook of a mustard keen professional.