These reckless thrillseekers are risking their lives by scaling the city's rooftops.
The actions of the daredevil group have been slammed as the “height of stupidity” after The Argus tracked down their boastful pictures online.
Andy Reynolds, director for prevention and protection at East Sussex Fire and Rescue, said the climbers were “irresponsible and reckless”.
He added: “It's the height of stupidity. We cannot afford to be attending potential callouts to people like this when there are serious emergencies taking place across the county.”
The apparently fearless youngsters, aged between 14 and 24 and mostly from Brighton, defended their behaviour by claiming they were “experienced” and “knew their limits”.
The Argus has uncovered videos and pictures of around ten parkour freerunners jumping on rooftops, freestanding pillars and industrial cranes.
During the latest stunt on Saturday night, a group of boys were snapped climbing on the rooftop of the 17-storey Hereford Court tower block in Hereford Street, Kemp Town.
Sussex Police received a complaint but said no criminal offence had been committed.
Eyewitnesses at the nearby Sidewinder pub described how the boys were “jumping from the rooftop to a pillar”.
When The Argus tracked the group down, they admitted previously scaling other terrifyingly tall structures, including the Brighton Wheel and a crane on the building site of the New England Quarter development site in Fleet Street, Brighton.
In a video posted on YouTube last week, the group can be seen scaling the giant crane without any safety equipment.
They dangerously dangle their legs over the top of the crane, peering perilously down to the street below.
In other pictures uploaded to a photo sharing website, they can be seen dangling with one arm from the top of another tall building in Brighton.
The photo is captioned: “Sorry Mum”.
Sacha Powell, a member of the group, said scaling structures was “simply fun”.
The 19-year-old, freelance filmmaker, said: “We do this simply because it's fun. When you overcome a new challenge you are filled with a great sense of achievement.
“We assess every situation with great detail and only proceed if everything is okay.
“We've been training Parkour for seven to eight years now. I started when I was 12.”
Asked whether he thought his group's actions were reckless, he said: “We say we're experienced, we don't do anything out of our limits and we know our limits perfectly.
“We climb for the lovely view at the top.”
Brian Snow, of Avalon Guest Accommodation in Upper Rock Gardens, Brighton, saw the group dangerously standing on top of the Hereford Court tower block on Saturday evening.
He said: “I just thought 'wow.' They had their arms out stretched and were jumping back and forth from a pillar to the roof.”
Gill Mitchell, Labour Councillor for East Brighton, said the group's behaviour was “reckless and akin to jumping from the groynes into shallow water”.
Inspector Gareth Davies, of Sussex Police, confirmed officers received a call from concerned residents in Kemp Town after the group were photographed on top of Hereford Court.
He added: “By the time we arrived they had gone.
"Our message is don't climb buildings and structures. It is extremely dangerous and a concern to the residents living in those buildings or nearby."
BOX - Sacha Powell, 19, a freelance filmmaker and Parkour enthusiast.
Parkour is about overcoming physical and mental obstacles whether at ground level or up at height.
It covers a great range of movements taking inspiration from other sports and art forms.
“It was founded in a suburb of Paris called Lisses but has evolved and grown worldwide into something much more broader than any of the founders anticipated.
“A common training day is based around simply having fun and going out, finding personal challenges and overcoming them.
“You only try what you know you're capable of doing. Knowing your limits comes with many years of practice. The fundamentals should be trained and drilled at ground level before taking it to a height.
“It might seem and look dangerous to other people. That doesn't mean it's dangerous for us. We've literally been living this stuff for years. We've practiced the techniques and movements required for the climbs a thousand times before taking it up at height.
“We know what surfaces and stuff to trust and it is important to know as we're trusting our lives with it. We rarely take risks with challenges at height. If it were really as risky as the public perceive it, the death toll of Parkour would be a great deal higher than it is.
“We try to limit little missions like this for night time to stay discreet and not to raise alert of the police, but sometimes it's hard to resist getting some amazing pictures and videos of the sunset over the city skyline.
“We have no great fear of the consequences enforced by police. They are usually very nice and understanding, and usually a bit shocked, but we usually stay discreet because we don't really want to have our fun at other people's expense.
“We appreciate that the police may have more important things to deal with.
“Some of us have normal jobs, like working in Tesco and I'm a young freelance filmmaker, and we vary between the ages of 14 and 24.”
What is Parkour?
Parkour is described as a “holistic training discipline” that develops one's ability mental and physical ability overcome obstacles.
It's thought to have been developed in the late 1980s in Lisses, a suburb of Paris, by Raymond Belle, David Belle and Sébastien Foucan.
The Argus used image manipulation detection software to check the authenticity of these amazing Parkour photos.
The software uses a range of methods to analyse a photo to see if there are any signs of the photo being altered.
The photos used in the newspaper were run through the software and no alternation was detected.