Luke Campbell is yawning. Luke Campbell is aching. The Olympic gold medalist confesses he is even nervous to be sparring. But the nerves of boxing don't engender fear; boxing nerves make you vigilant, alert – ready to erupt with jabs, straight-rights, and left-hooks. And boy, does Campbell have a left hook.

Luke Campbell may also be nervous because today is the first day of the biggest month in his boxing life. On the last day of this month, ‘Cool Hand’ Campbell will go up against Vasyl Lomachenko, the current WBA (Super), WBO, and The Ring lightweight champion, aiming to nab all three titles along with the vacant WBC lightweight belt. Lomachenko however, also happens to be, pound for pound, the best boxer in the world right now.

Campbell is tired because he’s been training hard for months on end. Yesterday he did ten rounds on the bags before a not exactly light workout. He is at the peak of his powers, and still relentlessly pushing.

Pre-training, he’s naturally sitting in Southpaw position: a right hand and foot instinctively placed forward. He’s watching tranquilly, speaking softly and staring, deep in thought, glancing deeply at the four corners of the coffee shop. His smile rarely leaves his face: Campbell’s time has finally come.

“I feel young and fresh. I ain't got many miles on the clock, and I've always kept myself in good shape out of the ring. I'm not a seasoned 31-year-old, I’m a young and fresh 31-year-old.”

He is at the peak of his powers, and still relentlessly pushing.

At 31, though, he knows this is not only the biggest fight of his career so far, but likely the biggest fight he’ll ever see. Victory this makes him unified world champion, cements him as one of the best, guarantees a set of main events to saunter into retirement with. Losing, well… losing has never been an option.

Since the day he stepped into the gym at 13, the boy from Hull has carried global ambitions. Eighteen years of dedicating hour upon hour to becoming the best have almost paid off: He stands at 5’9 with 20 wins, 16 KOs, no draws, two split-decision losses, and a title shot against the best in the world. He squirms at the statistic ‘two-split-decision losses’ – the squirm of a perfectionist unfairly snubbed.

“I could easily be sat here with 22-0-0, because both losses could have gone my way with nobody batting an eyelid, unfortunately it just didn't work out like that.”

Of the two losses, Campbell feels that his bout with Jorge Linares in the Autumn of 2017, was the toughest of his career. The match ended 114-113, 115-112, and 113-115. He still feels, nearly two years on, that he won seven of the 12 rounds in that night. He still feels that despite being put down in the second, he was on top in the ring.

“It was the toughest fight because of everything I had to deal with outside of the ring at the time.”

Less than two weeks before the fight, his father died following a battle with cancer. Campbell was training in the US at the time. He decided to stay silent, thinking the news could be seen as a weak spot. And so, Luke Campbell was waking, eating, training, sleeping with the weight of unimaginable grief punching against him. Punching against him with a force greater than any fighter could ever throw.

“I honestly have no idea how I dealt with it. I had to shut everything down, or I‘d get panicky: palpitations and stuff like that. I had to just fight. Looking back, I don't know how I managed at all.” He stares out of the window, looking upwards, rubbing his left knuckles with his right palm. “I probably should have pulled out of the fight.”

But Campbell is determined: not showing up was never an option.

“I thought it would have been something my dad would have wanted me to go ahead and do, so I didn't bother pulling out.”

I’m at the gym all day, and when I go home I keep training

Physical strength and fitness are obviously vital aspects of boxing, give or take the odd Butterbean. In the other corner, however, is the psychology of the sport. “Mental strength is probably the most important part of this sport, it carries you a very long way.” Campbell attests, having previously considered psychological strength 85% of being a boxer, and the hardest part to learn, during an appearance on Sky Sports’ Toe2Toe Podcast.

Although admitting he is training psychologically: actively thinking about himself, his conditions and his practice, he doesn’t give specifics. Some people have sports psychologists, we don’t know if he does. We do know that, mentally, Campbell is one of the toughest there’ll ever be, in this respect, he’s probably got the 85% in spades.

Campbell is making a conscious effort to not dwell on the past these days, to focus on himself, and to constantly improve. Like all top athletes, he is hungry.

This, naturally, means a lot of hours. This, naturally, means a lot of sacrifices.

“I’m at the gym all day, and when I go home I keep training. I want to be, I need to be doing everything as well as I can. Perfection takes effort.”

Luke Campbell cites no boxers as a direct influence. Sure, he watched Muhammad Ali, Sugar Ray Leonard and Roy Jones Jr, but they were just entertainment ‒ inspiration came far closer to home.

“I looked up to my mam more than anyone because she was the one who was working for the family and grafting, providing for us all. I always have a vision of her work ethic and ability to provide. That is my main inspiration.“

And how does Campbell turn off the taps of such unwavering work ethic? It’s simple. He doesn’t.

“I have a family. My kids keep me very busy. I just switch off by spending time with them and my wife. I'm a dad when I'm with them, not a boxer. After the weekend I'm a boxer again.”

The family are supportive of his career. They understand he needs to live in London during the week, and appreciate how he takes the near 200 mile journey home to Hull every weekend. His eldest even wants to come to the fight, but he doesn’t want his children boxing.

I make a lot of sacrifices. A lot of things can happen in the ring

“I make a lot of sacrifices. A lot of things can happen in the ring.” He speaks of both the physical danger and social sacrifices, but he is open to his son watching the match. “Maybe watching will toughen them up,'' he chuckles.

As the interview comes to an end, Campbell looks restless. He’s gazing beyond the cafe and out the window, towards the street the gym is on.

“No boxer really wants to do anything other than get stuck into the training, but it's part and parcel in sport, the media is everywhere. You've gotta do it, and if you're getting interviewed you're doing something right.”

Luke Campbell is yawning because he is doing everything right. There’s an itch that keeps people like Campbell awake. Knowing that every twitch of a muscle, every nanosecond shaved off a reaction time, has to not just match but exceed those of the greatest boxer of this generation. Come and the king, you best not miss.

Add to this, an experienced over-thinker. The understanding that to practically everyone, you are the underdog, and that you need to win if you’re ever going to truly make a legacy. Add knowing that being a champion as you near 32, is a world away from losing to the champ in your last month at 31. It is a pressure and insecurity unlike any other, it means putting in superhuman effort, or not turning up.

Campbell doesn’t flinch at the prospect of defeat. “I'll be able to live with myself knowing I've given it one hundred percent. And I'm giving everything I can possibly give in training.”

But if he can win. If Luke Campbell from Hull can beat the man widely considered unbeatable, more challenges await. Not least, dealing with them fame that comes with a new-found status.

“And then there’s retaining it, which is harder than winning it,” he chips in. “But that’s what I want to be known as, as a solid world champion, one of the best. That's all I've ever wanted to be known for. And going up against the pound for pound world number one is the best place to start.”

We sit in silence for a second, tasting the adrenaline and anticipation in the air. Feeling the fact that this month is where everything can change for Campbell.

“The only thing that'll change is that I'll be unified world champion. I’ll still be Luke Campbell of Hull, I’ll just be more known and I’ll get some more mega-fights to my name.” He stands up, says goodbye, and leaves for the gym.

Luke Campbell is yawning as he straps on the gloves, because his shift is just beginning.

Luke Campbell will face Vasyl Lomachenko on August 31 from 10pm, at the O2 Arena London. The event is being broadcast on pay-per-view by Sky Sports Box Office.