Eddie Hearn is talking excitedly at his grand Essex HQ about his plans to invade American boxing from a new office near Wall Street.

His father, Barry, meanwhile, has been chuckling and reminiscing.

“He used to be running around this place in shorts as a toddler when it was our family home,” Hearn Sr recalls. “Now look at him. He’s even taken over my old office.”

A frantic 12 days are looming for the Hearn family’s Matchroom boxing empire. A week on Saturday, 78,000 people will pour into the Principality Stadium in Cardiff to watch Anthony Joshua continue his quest to become the undisputed heavyweight world champion against Joseph Parker.

A week earlier this Saturday, Dillian Whyte, the fighter against whom Joshua catapulted himself to national prominence in 2015, will meet the former Sydney bouncer, Lucas Browne, at the 02 Arena in London. It could be a raw, old-fashioned kind of scrap and 8,000 tickets have been sold.

When Hearn Jr, who has hugely expanded the fight business begun by his dad in the 1990s, considers these sales figures and the forthcoming sell-out nights involving Amir Khan, David Haye and Tony Bellew, he insists: “Premier League football apart, boxing is probably the hottest sport in the country right now.

“We’re spoiled. There are so many big occasions. Okay, sometimes you have to pinch yourself and ask — are we really doing another near-80,000 event for AJ? But there is so much boxing everywhere and it is not just Sky TV showing it. There’s BT, ITV and Channel 5, too.

“It is all there from the big crowds at the big nights to the kids going into the grass-root gyms and saying, ‘I want to be like AJ.’

“We are the envy of the boxing world. We fill stadiums and arenas across the sport and the atmospheres are great.

In Pictures | Anthony Joshua's professional fights 25 show all In Pictures | Anthony Joshua's professional fights 1/25 Every professional fight of Joshua's career... Getty Images 2/25 Fight one vs Emanuele Leo Round One TKO, 2mins 47secs Kevin Quigley/Daily Mail 3/25 Fight two vs Paul Butlin Round two TKO, 0 min 50 secs Scott Heavey/Getty Images 4/25 Fight three vs Hrvoije Kisicek Round two TKO, 1min 38secs Scott Heavey/Getty Images 5/25 Fight four vs Dorian Darch Round two TKO, 0 min 51secs Rex 6/25 Fight five vs Hector Avila Round one KO, 2mins 14secs Mark Runnacles/Getty Images 7/25 Fight six vs Matt Legg Round one KO, 1min 23 secs Graham Chadwick/Daily Mail 8/25 Fight seven vs Matt Skelton Round two TKO, 2mins 33secs Paul Thomas/Getty Images 9/25 Fight eight vs Konstantin Airich Round three TKO, 1min 16secs Chris Brunskill/Getty Images 10/25 Fight nine vs Denis Bakhtov Round two TKO, 1min 0 secs Adam Davy/PA 11/25 Fight 10 vs Michael Sprott Round one TKO, 1min 26secs Kevin Quigley/Daily Mail 12/25 Fight 11 vs Jason Gavern Round three KO, 1min 21 secs Nigel Roddis/Getty Images 13/25 Fight 12 vs Rafael Zumbano Love Round two TKO, 1min 21secs Nick Potts/PA 14/25 Fight 13 vs Kevin Johnson Round two TKO, 1min 22 secs Kevin Quigley/Daily Mail 15/25 Fight 14 vs Gary Cornish Round one TKO, 1min 37secs Kevin Quigley/Daily Mail 16/25 Fight 15 vs Dillian Whyte Round seven KO, 1min 27secs Kevin Quigley/Daily Mail 17/25 Fight 16 vs Charles Martin Round two KO, 1min 32secs Richard Heathcote/Getty Images 18/25 Fight 17 vs Dominic Breazeale Round seven TKO, 1min 01secs Richard Heathcote/Getty Images 19/25 Fight 18 vs Eric Molina Round three TKO, 2min, 02secs Peter Byrne/PA Wire 20/25 Fight 19, vs Wladimir Klitschko Round 11 TKO, 1min 45secs Getty Images 21/25 Fight 20, vs Carlos Takam Round 10 TKO Action Images via Reuters 22/25 Fight 21, vs Joseph Parker Points decision PA 23/25 Fight 22, vs Alexander Povetkin Round 7 KO AP 24/25 Fight 23, vs Andy Ruiz Jr First career defeat, Round 7 TKO PA 25/25 Fight 24, vs Andy Ruiz Jr AJ regains his WBO, IBF and WBA (Super) titles, unanimous points decision. Action Images via Reuters

“You can go to a show in America and half the people in the place don’t even know who is boxing. It’s just something put on for TV coverage, not an event and an occasion in itself like we have here. That’s why our next move is into the USA. We’re opening an office in Manhattan in May. But we won’t take our eye off the ball here.

“Perhaps it will be hard to sell any more tickets than we are at the moment. But we mustn’t be complacent.”

Joshua and Hearn, 38, are not the only show in town in this thriving era for the British fight game.

On April 14, the newly-rejuvented WBO middleweight champion from Hertfordshire, Billy Joe Saunders, is promising a rip-roaring night against Martin Murray, also at the 02 Arena.

Under the promotional banner of Frank Warren, Saunders may be a serious contender to meet the winner of the forthcoming rematch in Las Vegas between the superstar pair Gennady Golovkin and Saul ‘Canelo’ Alvarez.

Meanwhile, Tyson Fury, the former world heavyweight champion, is succeeding in his quest to rejoin the fray if the latest pictures of his newly slimmed frame at work in the gym are reliable evidence.

This is the landscape of the boom. But it is the 28-year-old knockout king Joshua who is the household name, the poster boy for a new form of boxing promotion which has made him one of British sport’s most valuable marketing commodities away from the ring.

The story is a compelling one, which is why it was turned into a TV commercial by Lucozade, one of AJ’s many sponsors. In short, troublesome street kid discovers amateur boxing, wins Olympic gold and seizes the chance in just his 16th fight to become IBF world champion. Then he fills Wembley and stops the great Wladimir Klitschko, to add the WBA belt and become front-page news. Now, he has the opportunity to add Parker’s WBO title to his list but the Kiwi, of course, is undefeated.

“I think it is AJ’s toughest fight,” says Hearn, who brims with energy, which is why a revamp of rugby league may be the next project to accompany Matchroom’s interest in darts, snooker and boxing.

“I am nervous about the Parker fight,” he says. “We know that Anthony has vulnerabilities. He doesn’t deny that. But then he’s only had 20 professional fights. He is moving at a ridiculous pace, really. But you can’t slow it down.

“Not in this era of social media and so much popularity for boxing. This is the way the public wants it. He wants the biggest and hardest fights now, too.

“This is the buzz as a promoter in the heavyweight division. It is the danger zone. You can lose it all in one split second.”

The public will whip themselves up for the Parker fight but they are already looking ahead to a potential showdown with Deontay Wilder, the unbeaten American WBC champion.

This is the biggest prospect in boxing, provided Joshua defeats Parker.

Wilder, a whirlwind with his long, awkward reach, can whip up a storm of hype and trash talk outside the ring, too. He will be here next week and at the ringside in Cardiff to do just that.

Hearn knows the commercial value of all this bluster. But he has to gauge some limits to the frenzy.

He says: “Wilder will want to cause a scene. He will cause mayhem. But there is no way I will let him in the ring for any kind of showdown after Joshua and Parker have fought, whoever wins. That would be disrespectful. He can shout and holler from the side.

“If Anthony wins, he’ll get some back over the ropes. Josh has this humble persona but he still wants to destroy Wilder.

“But it is all about Joshua versus Parker for now. And I would say that Parker is better technically than Wilder — but Wilder is more dangerous. If AJ wins, I’d like to see the Wilder fight happen in 2018.

“It is the biggest fight in world boxing. Just imagine if Anthony were attempting to unify every title in only his 22nd fight. That would be unbelievable. But let’s see if we can get past Parker first. Other plans just have to wait.”