In 2017 Clarke and his GB team-mates were boxing Italia Thunder in the World Series of Boxing at the venerable east London venue.

The day before the British team had been at a charity event at the Houses of Parliament. They were caught up in the Westminster terror attack, when as they were leaving, in front of them an attacker repeatedly stabbed PC Keith Palmer before being shot dead.

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Tony Davis, one of the GB coaches, was one of the first people to reach Palmer and attempt to treat injuries that ultimately proved fatal.

"To box afterwards, it was surreal. It's only when you get a little bit older and you look, you think: 'Oh my God, how did I box the next day?'" Clarke told Sky Sports. "Looking back now I don't know how we did it.

"I was bit youthful, a bit younger. The WSB, remember that was the only chance as amateurs to earn an extra few quid as well and we were all skint."

The decision to still go through with the event was taken by the boxers. "I was with a team," Clarke said. "I'm very close to them, I was with Callum French and Pat McCormack. They come from the hardest place in the world, in Birtley.

"We were all asked the question. 'Is everyone okay to box tomorrow? We can cancel this show, not a problem.' Their hands went up straight away and mine followed straight after.

"Nothing was going to deter us. You're youthful then."

They won the team match 5-0, with Clarke beating top Italian Olympian Guido Vianello.

This came in an early stage of an Olympic cycle which would culminate a special group of GB boxers winning six medals at the Tokyo Games. Clarke became the captain of the team and an Olympic bronze medallist himself.

"That was just one of the instances in the character of that team. Even though Callum French didn't go [to the Olympics, after his weight class was removed], he was such an important person in that cycle. A really, really good, solid fighter, really good team member and there was a lot of them during that cycle, Cyrus (Pattinson), Callum French, other people that really, really played a big part.

"They played their part."

Clarke, of course, is now a professional fighter, a lonely trade and is navigating his way through the early stages of his career. He returns to York Hall on Friday night for his seventh pro contest.

Still just 6-0 Clarke came under intense scrutiny when his team elected to withdraw from a purse bid for a British title shot. He does want to fight Fabio Wardley for the British championship, but understands the importance of getting more professional rounds in first.

"That tough 10 days of social media with the Fabio stuff put the bit between my teeth," he said after a deluge of comments on social media. "I had a real tough 10 days and that's made me grit in a bit."

It stung his fighting pride but Clarke said: "I'm long in the tooth because I've been around for so long. I've had bad things happen to me, good things happen and I learned from all the experiences so it's not a problem. I just take it with a pinch of salt. It took me a few days. I'm only human.

"As far as amateur boxing careers go, I've been through the mill. The terror attacks. I was stabbed myself. The kerfuffle at the world championships with Maxim Babanin [when Clarke was denied a medal after a controversial bout review]. The Olympic heartbreak - twice."

On Friday he must keep his on focus on his next opponent, Polish heavyweight Mariusz Wach.

"I've got a 20 stone man in front of me who's going to try to punch my head in." That, Clarke is convinced, will concentrate the mind wonderfully.

Wach is known for his resilience and Clarke is going into his first scheduled 10-round contest with the veteran, live on Sky Sports.

It should give him the professional experience he's looking for.

"He's a perfect example of what you see is not what you get. He doesn't do what it says on the tin," Clarke said of Wach.

"He's an old pro who knows his way round a ring and he sets a good pace for a big man. He lets his hands go at times in a fight. He has experience of when to punch, when not to punch. He does a lot of good things. He's not the fighter he once was, let's make no mistake about it, but a stern test.

"The thing about the heavyweight division, the world is quick to judge. Because we don't all look like Anthony Joshua with a 10 pack and muscles coming out of your chest," he added.

"Between the both of us there's not a Calvin Klein contract coming, it's not happening. But we're fighters, he's a proud man, I'm a proud man."

He wants this contest to set him up for future title bouts. Wardley remains in his sights.

"I know it's going to be a big fight," Clarke said. "That fight has to happen.

"It's the domestic Joshua and Fury. Everyone's calling for it. So it's going to happen. 7-0 novice pro in me and him on 16-0, it's made a lot of noise and I relish it. I look forward to it.

"But I've got to deal with Mariusz Wach."

Animated when thinking about his future goals, Clarke declared: "People think I don't have ambitions! Especially these domestic lads - they can't lace my boots. I'm telling you now, time will tell and I'll prove it.

"It makes my heart beat fast when I talk about it. Why can't I be a world champion?" he continued. "It's only on me. If I fail it's because I've been lazy and took my eye off the ball."

He was a world-class amateur, he has the boxing calibre. "I've the platform, I've got the good people around me," he continued. "I've got a fantastic coach [Angel Fernandez] that will emerge shortly and make Richard Riakporhe a world champion, 100 per cent. He'll make me a world champion.

"Then we'll all get the credit we deserve."

Watch Frazer Clarke vs Mariusz Wach live on Sky Sports Action from 7pm tonight.