Brad Thorn© Photo by David Rogers/Getty Images

Old Father Time is a cruel beast. For every rugby player, professional or amateur, there comes a moment when the body finally sounds its ultimate protestation but there are some players who you never think will retire. They seem bulletproof.

It is alarming to hear 40-year-old Brad Thorn contemplate his own transience. The great All Black and league legend, sits in the clubhouse at Farnborough RFC, smiling and reflecting. Though Farnborough is thousands of miles away from his childhood home in Brisbane and his birthplace in Mosgiel in New Zealand's south, whenever he is at a amateur rugby club, it feels right.

"For me my thing with rugby has been to take on professionalism but not to leave behind the awesome culture it's had for 100 years," Thorn tells ESPN. "You have to marry in with the great culture that is rugby. That's what I like to see with rugby. When you get that right... the fabric of rugby is really special. The people are the big thing for me. That's the thing I like the most: the friendships and the people you meet."

Thorn has just taken part in Land Rover's launch of the Rugby World Cup where a series of the game's legends arrived at Farnborough to surprise an amateur club. After the match finished, Thorn politely asks if he can get himself a beer before we sit down. Despite the reluctance of the barman, Thorn pays for his pint. Then to the barman's joy he poses behind the bar in the mock pulling pints pose.

During the day, Thorn saw a 66-year old man running around. Sitting as someone 26 years his junior, Thorn jokes he might carry on for another 25 years, but to rugby's loss, he adds: "To be honest I'm thinking about hanging up the boots up this year. I have been doing this for 22 years now. Maybe I just need to let other guys do it."

Just who the "other guys" are is rugby's question to answer. Thorn has achieved unrivalled success in both codes of the game. He has won a series of NRL Grand Finals with the Brisbane Broncos, a club he is an honorary life member of. He has also been on the winning side in the State of Origin. In union, he was the first player to win the trinity of a Super Rugby title, with Crusaders, a World Cup with New Zealand and the Heineken Cup, at Leinster.

The young Brad Thorn was an ambitious kid. Growing up in New Zealand, it was hard for young men to escape the gravitational pull of the All Blacks shirt. But a move to Brisbane at the age of nine meant his goals swung from union to league. Now as he approaches the final straight in a 22-year career, what he has achieved is "far beyond" his dreams.

Thorn has used different parts of the game as motivation along the way, his inspiration changing year-on-year, decade-on-decade. "I'm just playing for the love of the game these days," Thorn says of his current stint at Leicester. He loves to compete - with the opposition or against himself.

"It's not just the team winning but it's me personally competing," Thorn said. "It's now me competing against age. No one can halt Old Father Time. I've always looked for many things to compete and anything I can grab for a drive. I love physicality. But the number one thing I love is camaraderie.

"It's a selfless game. For the front-rower to do well, he needs me to push my heart out for him. For me to do well in the lineout, I need him to do well. For the half-back to do well, he needs me and my mates to sort the breakdown for him. For the backs to do well, they need good hands from the half-backs. It's a selfless game, but it's a physical game which forces camaraderie. You have to play for each other; you have to do little things that don't get noticed. I love seeing the guys five years on when you look them in the eye you have that trust and connection."

Time is now taking its toll on Thorn mentally, but he feels strong. "I feel good, my body feels good," he says. "I'm pleased with my form for the Tigers - I feel it's matched anything I've done in the last five years.

"My home is Brisbane. In rugby, people know me as an All Black but I left New Zealand when I was nine. All my high school life was in Australia. I have four young children. We've been away for about eight or nine years now. I could easily stay here, I could be in Europe if it was just me and my wife but it's getting time to take the family back, get a pet dog, a Labrador. We've lived in Japan, we've lived in Ireland, Christchurch, Dunedin - it's time for a family home and to set that up."

Whatever family home he opts for in Brisbane, it will need a custom-made trophy cabinet. He namechecks the Grand Final wins in NRL as career highlights, alongside the Super Rugby titles at the Crusaders. There is also his Heineken Cup win with Leinster - "when I held up the cup with Brian O'Driscoll, that was just gold". But, in addition to the mantelpiece silverware, he has his own mind-palace of achievements: "In Japan we came last in the comp but I poured my heart into it. The whole package is why I'm still here."

Brad Thorn and Felipe Contepomi© Photo by Steve Bardens/Getty Images for Land Rover

One achievement he does not refer to is the 2011 Rugby World Cup. "The World Cup wasn't really like that for me, it was a duty to my country," he says. "There was too much on the line. There's too much at stake.

"I was a senior member of that team and it was a job I just had to get done and then move on with my life. Even to my team-mates, I knew I couldn't show any weakness. I didn't sleep very well, I was pretty much run down by the time we reached the final. The pool stage was fine but when we reached the quarter-finals I shut myself down, it was business time. I was in tears after the whistle in the final and that was because I had put so much pressure on myself."

When the tears stopped flowing, he changed his mindset. "I've done my causes, since then I've had fun. I don't apologise for it, I've just had fun." So what next? When Thorn retires, probably later this season, he will consider coaching, but is unsure whether the cut-throat nature of the role is right for him.

It will be to rugby's detriment when he eventually decides to call time on a unique and wonderful adventure but the man himself will go with no regrets. "There have been so many good moments," he says. "I've worked hard. Before I was born, I didn't say 'I'll have this body shape and this father who inspired me and this coordination and I'll go uninjured'. I'm humbled, I thank the Lord for what's happened. I've worked hard on it. I've just loved it the whole way."