How safe is bare-knuckle boxing as it fights for mainstream appeal?

“One punch could change your life. But I love the sport.”

Bare-knuckle boxer Liam Rees is aware of the dangers when he steps onto the canvas.

The Welshman juggles his day job as a carpenter with the demands of a sport so visibly brutal it has stayed in the shadows of combat sports for much of its existence.

Slumped in a chair moments after losing his light-middleweight world title at the Vale Sport Arena, Cardiff, the Swansea native’s wife Emma gently implores her bloodied partner to give up the sport.

“No more now babe,” she says.

But nothing can replace the buzz for him.

“You’ve got so much adrenaline pumping through your body in that ring,” he tells BBC Sport.

“Some people think I’m crazy.”

At licensed bare-knuckle events, fighters go toe-to-toe on surfaces half the size of a professional gloved boxing ring – which means there is nowhere to hide.

There are more cuts, bruises and knockouts – which is exactly the appeal for some fans.

After overcoming substance-abuse issues, the 31-year-old was introduced to the emerging combat sport by a trainer in his boxing gym.

He made his bare-knuckle boxing debut in 2023, going on to become a two-time light-middleweight world champion in BKB.

During camp, Rees trains three times a day, five days a week, forgoing seeing his two children on weekdays.

He does not earn enough from the sport to quit his carpentry business. His goal is to leave a “legacy, just to prove to the city I’ve done something for them”.

Bare-knuckle is the oldest form of boxing but became associated with unlicensed fights on wastelands after The Marquess of Queensberry rules were introduced in 1867, which insisted on gloves.

However, in the past decade, licensed events have grown. As per data from BoxRec, there were only 21 licensed bare-knuckle bouts in 2015. Last year, the figure was more than 1,000 across 21 countries.

Rees fights under the banner of Bare Knuckle Boxing (BKB) promotions – one of two major international promotions who host licensed bouts, alongside US-based Bare Knuckle Fighting Championship (BKFC).

Attendances at BKB venues are capped at 2,000 and the organisation’s president David Tetreault says they generally sell out.

Broadcast in more than 60 countries, BKB has partnerships with the likes of VICE TV and TalkSport.

Retired boxing world champions Lee Selby, Paulie Malignaggi and James DeGale have all crossed into bare-knuckle boxing as the popularity grows.

However, Luke Griggs, chief executive of brain injury charity Headway, said he is “hugely concerned” about its rise and the “glamourisation of a sport that’s going to be taken out into the streets”.

In a new film, BBC Sport investigates the realities of a sport that is slowly becoming more popular, and the people at the heart of it.