The emergency services performed a daring rescue at 170ft as crowds gathered at one of Islington’s most famous gig venues to witness the dramatic incident.
A hazardous area response team rushed to the scene and ladders were sent to the top of the spire to bring the man down.
He was then treated at the scene, before being rushed to the University College Hospital in Euston as a priority.
Leon Shoben, 55, who works at the Elfrida Society, an educational facility in nearby Islington Park Street, said: “I was walking back from Highbury and Islington station with a class and I saw a lot of people looking up at the ladders and the fire engines.
“I thought the scaffolding had collapsed at the top, it looked like the people up there were moving a lot of stuff around. There were a lot of ambulances there.”
Daniela Sbrisny, duty manager at the Union Chapel, said: “We were the last ones to find out. One of our colleagues was outside and told us that someone had collapsed on the scaffolding.
“We ran outside to see if there was anything we could do, but by that time they were bringing him down on the big fire ladder.”
A spokeswoman for the London Ambulance Service said: “We were called to reports of a person taken unwell on scaffolding at the Union Chapel. We sent a motorcycle paramedic, an ambulance crew and our specialist hazardous area response team. The patient, reported to be a 50-year-old man, was unconscious at the top of the scaffolding.
“Our crews climbed ladders and scaffolding to reach him at the top of the spire which is 170 feet tall. They helped move him to a fire brigade platform where they treated him before he was lowered to the ground. He was taken to University College Hospital as a priority.”