Sam Warburton leans forward in his chair and looks wryly into the future. "It's going to be talked about for the rest of my career," he says when asked if he fears being haunted forever by questions about him being controversially sent off in the semi-final of last month's Rugby World Cup. "Even when I'm doing a Q&A at a rugby club in west Wales it's going to be brought up 30 years down the line. It's already a massive event in rugby history. But I can only speak about it honestly."

Warburton, at 23, is the most impressive young player in the world. Beyond his rise over the past year from an inexperienced Cardiff Blues squad member to Wales captain and an openside flanker now bracketed among the great current-day No7s, his reaction to that dismissal has been admirable.

He was shown his red card after 19 minutes in a game against France that Wales lost 9-8. "People know I'm not malicious," he says. "But since I've been home I have looked at it a few times and nod my head every time. It didn't feel half as bad as it looked – if that makes sense."

Warburton is not a hulk but, in tackling Vincent Clerc, his momentum lifted the France wing off his feet. It was only midway through his tackle that Warburton realised something was awry. "When he went up in the air I thought: 'Crikey, he feels quite high up.' I didn't know what to do. So what I did next was a mistake but I thought: 'I'll just let him go and compete for the ball.' But I released him from three feet in the air rather than the one foot allowed in the rule book. I never expected the red card because it was a tip tackle – not a spear tackle. But it's a grey area and I can't complain."

He found the resolve not to show dissent as he made the lonely walk from the field. "In the Under-20 World Cup I gave away a penalty and the camera zoomed in on me as captain. My mum saw me swearing on TV. So in a World Cup semi-final I knew it would be best not to criticise the decision. But, internally, I didn't know what to think. Obviously there's embarrassment as well. Besides injury, you couldn't imagine anything worse happening to you as a young captain. If we'd had 15 men we would have been very confident of winning that game."

His mother's reaction chimed with the emotional mood in Wales. "Mum and Dad flew over especially for the semi-final. They were meant to be my lucky charms. Mum was really angry but she doesn't understand rugby as well as Dad. He was gutted but he could appreciate that, by the letter of the law, it was a red card. Mum was just furious. She felt sorry for what I was going through – but it hasn't affected me that badly. The support has been great, with people saying how well I've handled it. But that surprised me because I thought there was no other way to handle it."

Fate tested him again when he flew from New Zealand to Australia to catch his connection home and ended up alongside Clerc. "As I put my baggage in the overhead compartment he was laughing and obviously thinking: 'What are the chances of this happening?' His seat was next to mine with only an aisle between us. Jokingly, he asked for a massage. We shook hands and spoke for 10 minutes – mainly about club rugby. He's a good bloke and there're no hard feelings. A lot of the French guys on the plane shook my hand and said: 'Well done on the World Cup.'"

That acknowledgement of Warburton's stature as one of the players of the tournament should be renewed this Friday evening when, following his three-week suspension, he returns to play for Cardiff in their opening Heineken Cup game – at Racing Métro in Paris. "It'll be interesting to see how they take to me out there," Warburton says. "But I look forward to it. I've only played against two French clubs so far: Castres and Toulouse."

Warburton revels in his new status in the game. He is also amused by the impact on his family. "Mum, Dad and my [twin] brother Ben are doing more interviews than me. They could do with an agent soon. But they've enjoyed it. They certainly didn't see this happening a year ago. I wasn't even starting for the Blues in certain Heineken Cup games and the Welsh captaincy came completely out of the blue."

Yet, in New Zealand, Leigh Halfpenny said he'd never forget how, before an Under-19 game, an inspirational Warburton had reduced him to tears. "I remember the speech," Warburton says cheerfully. "Rowland Phillips was the coach and he shook my hand and said: 'Well said.' I was like: 'Really?' A lot of players said: 'You spoke amazingly,' and I was like: 'Did I?' I forget what I said but it won't have been long and flowery. Some people talk for the sake of talking. I only speak when I feel it's appropriate."

Such succinct clarity is evident in the discipline Warburton and his young squad, built around a core of players aged 23 or under, displayed during the World Cup. "I'm glad you say that," Warburton murmurs. "People say it's me, but Dan Lydiate, Toby Faletau, George North, Scott Williams and Lloyd Williams are just as professional. That makes my job so easy."

Warburton was instrumental in binding them together on a gruelling training trip to Poland, where he persuaded his players to endure extra sessions in ice chambers where the temperatures were minus 140C. Yet he is most interesting in the way that, despite being essentially solitary before matches, he has learnt to galvanise his team-mates. Warburton tells a story of how his girlfriend, Rachel, once persuaded him to go to Starbucks on the morning of a game – "to take my mind off the match". He played badly that day and swore he'd never make the same mistake.

How has he managed to combine captaincy with his preference to be alone before games? "I talk to Andy McCann," he says of the team psychologist. "A big part of me taking the captaincy was the fact Andy went to the World Cup. He has a real calming influence on me and I saw him a lot in New Zealand. Sometimes I turn up and he can just tell I don't need any priming. I'm in a good state. If I'm a bit nervous he'll do more then. He reads my body language and he's been a huge help."

Welsh prospects are now giddily high. "If there was a World Cup next year we would want to win it," Warburton says. "That would be a realistic target. Six months ago people would've thought we were having a laugh."

England, in contrast, were abject, with their World Cup failure linked to off-field misdemeanours which included drunken exploits at a bar featuring dwarf-throwing. "England probably saw themselves as the best northern hemisphere team before the tournament. So they'll be disappointed. I don't know what went on – you'll have to ask their players. Those antics might be seen at the end of a tour, but even then it would be pushing it. You'd never expect that after a first game. You'd think their priorities would be looking forward to the next match. Their behaviour surprised me because we knew the media would be on the lookout – which is why we stayed in and had a couple of cheeky ones in our hotel."

The Welsh were only riotous when singing. "It wasn't just choir practice," Warburton says. "Whenever we had a Maori welcome we'd answer with a traditional Welsh song but for our own amusement it was always Lady in Red. All 50 of us would sing it. I've got a video on my phone of Dan Lydiate singing it in our room.

"Might have to put that on the internet sometime. Normally I like Metallica but when you're away for seven weeks, without girlfriends and wives, the boys get a bit emotional."

Rachel is an intrinsic part of his life. "We've been together since school – and started going out at 17. We were always in the same class and actually lived four doors from each other. I chased her for two years before she'd go out with me. She finally realised I played rugby and said: 'Oh, go on then.'"

He laughs. "At 17, I told Rachel I wanted to be a rugby player but she never realised I'd make it this far. I've surprised her. And as soon I got back last month I went straight to London with Rachel for four days. She didn't go to New Zealand. She was honest and said: 'I'd rather you spend the money on me when we get to London.' It was a lose-lose situation for me."

Warburton cackles infectiously again. "No one knows who I am in London so we could walk around like normal people."

His parents were both born in England and Warburton is a passionate Tottenham Hotspur fan. Long before his schoolboy friend Gareth Bale joined the club, Warburton had been Spurs-crazy. "I got my first Tottenham shirt aged five with 'Sam' and '9' on the back. If I couldn't be a rugby player I'd love to play for Spurs."

Bale, meanwhile, has had an extraordinary few seasons. "I was mates with Gareth," Warburton says. "We had five years of school together, doing our GCSEs, playing in the school football team and having the same friends. Apparently he always said if me and my brother didn't play in defence we'd lose – so I'll hold him to that. Me and Ben were no-nonsense defenders."

A bit like Tony Adams? "Exactly," he exclaims before realising the horror of an Arsenal link. "No! Like Sol Campbell."

Warburton covers his face. "Oh no, not Sol! My brother was devastated when Sol went to the Gunners. You'd better say we defended like the incredible Ledley King."

Does he speak much to Bale now? "We don't get the chance but he's still good friends with my good friends so we keep in touch indirectly. My whole family is Spurs mad. Dad once had a dog called Glenn – after Hoddle. The family now have two old dogs: Ted and Gus. They're named after Teddy Sheringham and Gustavo Poyet. I've moved in with Rachel and we're getting a dog. It will definitely be called Harry."

Few other dogs in Wales might be named after the Tottenham manager but it's a safe bet that thousands of puppies, and many more babies, will soon be called Sam – after a young giant of a rugby man.