Their battered faces are bleeding and shiny with sweat, their naked torsos covered in red wheals where violent punches have landed.
Front-row guests on £70 tickets are suddenly splashed with blood as one man’s cheek is ripped open - and they couldn't get enough of it.
Far from being horrified, these Saturday night revellers in a suburban Manchester sports arena are thrilled at the bare-knuckle fight which is now in its third round.
Close to 800 of them have gathered tonight at the Bowlers Exhibition Centre to watch 18 men box each other without gloves.
Brutal? Yes. Thrilling? Definitely. This is a sport where ribs crack, hands break, faces tear, shoulders dislocate, noses and cheekbones snap and eye sockets shatter, as young men fight it out in fast and furious combat for anything from £500 to more than £5,000.
With its roots in the ancient empires of Greece and Rome, bare-knuckle boxing has never been illegal in the UK but has no official regulator and is not governed by the British Boxing Board of Control (BBBC).
Exposed knuckles are not permitted in the UK, so fighters wrap bandages over them as protection. The rules are similar to gloved boxing in that biting, low blows - below the waist - and elbows are forbidden.
Tonight’s nine fights which are bloody and frantic are fought over three two-minute rounds with a 20 second recovery period after a knock-down (compared with 10 seconds in gloved boxing).
The crowd, all over-18, have paid from £35 to £70 for seats. There are more men than women but plenty of both.
'It's the true test of a warrior'
Hours before the fights begin, the fighters arrive for a weigh-in on a pair of simple bathroom scales, then undergo a medical and mandatory drug testing via mouth swabs.
After that they have the afternoon free - at least one of them pops to the nearby Trafford centre to do some shopping.
Fighters are guaranteed money: they’re paid a flat fee depending on experience, get a share of any tickets they sell, and have the chance to win prize money.
‘Mad’ Mark Franks, 43, is one of the big characters here tonight – a boxer, a bare-knuckle fighter, a trainer and Wakefield gym owner.
Tonight he’s with 30-year-old Ben Croft, who’s fighting bare-knuckle for the first time. Mark has been training Ben hard for tonight’s fight.
Ben served time in prison after an altercation in which a man died, and started life afresh in Yorkshire, where he works as a plasterer and lives with his girlfriend of three years.
“Bare-knuckle fighters like Ben are brave men, and the nerves you get at an event like this are off the scale compared with gloved boxing,” Mark says.
“It’s the true test of a warrior. Can you control your mind - because it’s not just about the fighting? Can you control your nerves enough to perform, knowing the dangers involved?
“It takes major cajones because you can so easily get injured. That’s why people come to see it – this is very risky stuff. It’s dangerous and it’s exciting - fighting is an animalistic thing.”
Mark, a strong, slight man with stripes shaved into his head, says bare-knuckle boxing attracts men who might be ‘rough round the edges’ but who, like Ben, need someone to believe in them.
Ben says: “I’ve been boxing for years and bare-knuckle seems to be where it’s at now, so I want a go at it. I’m nervous and I will be until the fight starts. It’s the unpredictability of bare-knuckle that’s unnerving.”
WAGs 'flipping out'
When Ben told his 25-year-old girlfriend Billie Jean Wright, a barber, that he was planning to fight bare-knuckle, she was so upset that she refused to speak to him.
“She had a flip-out again last night about me doing it but now she’s OK and she’s here with her mum to support me.”
Billie Jean says: “I’ve asked him not to do the bare-knuckle fights but he won’t listen to me. It scares me. I don’t want him to get hurt.”
Ben doesn’t get hurt – and wins his fight.
So does 30-year-old Dean Byfield, from Anglesey in Wales. He’s in a relationship, a father of three who works as a bin recycling man, and who’s trained hard for the last seven weeks to lose 3 stone and get himself fight-ready.
He says: “I’ve had some bad days. I was in the Welsh Guards in Afghanistan for seven months and went through some tough times there. I was bullied after school and in the army, but I can look after myself and I just like to fight. Win or lose, it doesn’t bother me.”
Like most wives and girlfriends, Dean’s partner hates him fighting. For now though, he chooses to ignore her objections.
Dinner lady by day, ring girl by night
One woman who’s totally into the fighting, however gory, is regular ring girl Heather Smith. By day a mum and school dinner lady, on Saturday nights she’s dressed in fishnets, a G-string tankini and black leather shoe-boots, with false lashes and blonde hair extensions.
Heather and her fellow ring girl accompany the boxers down the runway before the fight, in a blaze of fire and dry ice.
“I’ve been doing this at weekends for three years now and I love it. It’s good fun – as long as you don’t mind blood!” she says.
'It's like being stabbed with 1,000 knives
Bare-knuckle boxing is big business for ex-con Shaun Smith, the UK’s top bare-knuckle boxing promoter who, together with his wife Amanda, owns Ultimate Bare-Knuckle Boxing.
He runs a Warrington gym training men from Britain and as far afield as Lithuania and the US, in a controversial style of combat which has emerged from the shadows to enjoy a surge in popularity in recent years.
“Bare-knuckle is the ultimate test of a fighter. Taking that first punch, bone on bone, is like being stabbed with 1,000 knives,” says Shaun.
He's draped in gold jewellery, drives an all-black Land Rover and wears a black track suit with the words “Boss Man” emblazoned in gold on the back.
Shaun used to fight bare-knuckle, then went to jail for a firearms offence after his involvement in a Liverpool gang war.
He turned his back on crime after his release from prison 10 years ago, and set up his bare-knuckle boxing business seven years ago. He now stages three or four bare-knuckle events a year.
He’s a dead ringer for fellow-Liverpudlian Paul Hollywood (once jesting “Paul beats eggs. I beat people”).
A Vice documentary dubbed him “the UK’s scariest debt collector”, and Bare-Knuckle Fight Club – a Netflix look at his life and work – was trending not so long ago. A Hollywood movie is now in the pipeline, Shaun says.
This one-time club doorman is ecstatic that bare-knuckle boxing might join the mainstream in the same way that Mixed Martial Arts has gone from the underground to prime-time TV event.
“I used to bare-knuckle box myself and it has a bad reputation, but there has never been a single death in the history of bare-knuckle boxing,” he says.
'The buzz is off the scale'
He is refereeing tonight's fights and also sitting ringside are three judges, as well as a doctor and two ringside medics.
Roofer Joe Clarke, 31, has flown over from his expat home in Spain to fight.
He says: “I’ve been gloved boxing since I was 12 but I wasn’t getting a buzz out of it. I saw some bare-knuckle boxing online and tried it four years ago. The buzz from it is off the scale.”
IT consultant Stu Armstrong, the Smiths’ partner in UKBKB, says bare-knuckle boxing gets the fighters talked about.
“It’s the ultimate adrenaline sport - so much faster and more action-packed than gloved boxing,” he says.
Bare-knuckle boxing was popular until 1867, when the Marquess of Queensberry Rules were introduced which required gloves to protect the hands.
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Stu says: “All forms of boxing, kick, gloved or bare-knuckle, can be dangerous. But the dangers have been exaggerated. People belittle the sport on the grounds of safety but we run professional events overseen by trained medics – we take care of our fighters.”
Shaun Smith echoes this: “A long time ago we had pub fighters, but we do everything professionally now. We’re not fighting in the gravel. Even the people bandaging the fighters’ hands have been on a course.”