GETTY/Express Newspapers Darren Barker was an IBF middleweight world champion but now runs 12x3 gym in Aldgate

Fortunately, Darren only has pads on his hands and I am in his gym, 12x3, the name a reference to the 12 rounds of three-minute championship boxing he had to go through to win his title. Equally fortunately, he has no designs on putting me through similar toils in our hour-long session, my first real boxing training session. I had barely expected to get the gloves on in a first session. We did some skipping and some footwork drills - which included the question “orthodox or southpaw?” to which I instinctively threw my hands up left first, for no reason other than that’s how I shadow-box the galleries man who sits next to me in the office. We work on shuffling around the gym keeping the base solid and Darren points out when my feet cross over, creating a less steady position and one in which I am much more likely to be knocked over. He doesn’t demonstrate too graphically but there is enough of a sergeant-major undertone to his voice to keep me focused and working hard on this most basic but most fundamental skill.

“After that first year [of retirement], I had done a bit of travelling and had the time of my life, living without that discipline,” Darren tells me afterwards, perched on the side of the ring that sits in the glass-fronted window of the Aldgate gym. “But I had to get going again and I knew I wanted to stay within boxing in some capacity. “I was doing a bit with Sky Sports [as a pundit] that was all well and good but I was looking around and I could see these different gyms opening up and doing boxercise. “I thought to myself that I’d been so fortunate to have been trained by some of the best coaches out there at amateur and pro and I wanted to replicate that to the masses: to all-comers, to anyone who wanted to come down.”

I was one of them. I had initially met Darren and some of the 12x3 regulars in deepest, darkest Wales a few hours before Anthony Joshua produced his 20th career win over Carlos Takam at the Principality Stadium. A 40-minute drive up into the valleys and 10 minutes getting lost in an industrial estate later, we found a scrappy old working men’s club with a sign that bore the phrase “Joe Calzaghe Gym”. This was hallowed boxing turf. It was unapologetically modest, despite the fact that this had been the place to produce a man routinely known as the best super-middleweight of all time. Certainly, the list of opponents at the latter end of his 46-0 career certainly suggests as much: Roy Jones Jr, Bernard Hopkins, Mikel Kessler. He didn’t exactly make a career of bouncing out what Tyson Fury would call “bums”.

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The man himself has been called away to an “Evening With..” event but that does not mean the gym, and its pitch-black central corridor where the lightbulbs either haven’t been replaced or have never existed, is devoid of boxing royalty. His father and trainer Enzo is there, having just put some of Darren’s most loyal customers through their paces on the same canvas that Joe used to use. I wander through to what had been the back bar of the club, which is now covered in pictures and posters bearing the Calzaghe name. There are even a few drawings, done by Enzo himself, caricatures of himself and his son in their pomp. He continually drops pearls of boxing wisdom, talking almost obsessively about the 46-0 record. I ask him if it was difficult to balance being the boxer’s trainer and father.

Express Newspapers Joe Calzaghe's gym has little glamour but even smells of history

Express Newspapers The Welsh gym itself is easily missed, hidden away on an industrial estate in the valleys

“No,” he barks angrily and I think I’ve offended him. Fortunately, he’s demonstrating how he’d be with Joe, grabbing me by the shoulders and telling me if I didn’t like how he was training me, I could f*** off and find someone else to do the job. “Thanks, Da,” I reply in best Welsh. Next door in the gym itself, Joe’s son Connor is waiting and agrees to give us a lift back into Cardiff. On the journey back, which is longer due to the roads filled with boxing and Cardiff City fans - Joshua’s presence has not dissuaded the local side from scheduling a home game against Millwall. Connor jokes with us about some of the fights he’s been ringside for and the ridiculousness of the situations he was in. At one point, he remembers sitting next to Whitney Houston for hours before later realising who she was. “She’s my mum’s favourite singer. If I’d have got her on the phone, I don’t know what would have happened!”

GETTY Enzo Calzaghe says training his son Joe was tough but they remained close

GETTY Joe Calzaghe was knocked down early by Bernard Hopkins - with Whitney Houston ringside

That was back in 2008 but Barker and Calzaghe go back further than that and when he decided to open the gym, you can see that his Welsh friend’s old place inspired him. But he also recognised that in central London, he needed to accommodate for some softer hands. “I sat down with Ryan Pickard, who I’ve known for years and is club captain at Repton and we hatched 12x3: elite level coaching for all-comers,” Barker tells me. “It’s something we’re both so passionate about and it’s a nice environment to learn from the best - but also you go in the changing rooms and there’s fluffy towels and smelly soap and it suits the people who come here.”

Express Newspapers The "fluffy towels and smelly soaps" are a concession to the location of 12x3

He adds: “One thing with this was trying to get the mindset which you get from boxing: never giving up, the confidence of controlled aggression, the discipline, the respect. “There was a young lady who came down and she’d never ever boxed before. She was so intimidated to come down the gym as you can imagine. “I walked her in the door and said ‘you’re with me, don’t worry’. “You could tell she’d never boxed before but by the end of the session she was throwing shots on the bag, delivering proper, correct 1-2s. “I said ‘stop a minute. Look at that improvement. You couldn’t even stand in your stance at the beginning and now you’re throwing shots without me saying anything.’

Express Newspapers 12x3 gym brings elite boxing coaching to any who walks in the door