Retired police officer Hywel Jones was working on the roof of a house in September 2010 when he fell two storeys breaking his back, pelvis, arm and wrist.
The 50-year-old said: "The person who was footing the ladder went away for 20 minutes. It just proves how important it is to secure the bottom, because it slipped away and I belly-flopped on to the concrete below."
He was lucky the house was on a main road because people quickly came to his aid and London’s Air Ambulance advanced trauma team was at his side within 10 minutes of receiving an emergency call.
Mr Jones, who lives in Ruislip, also sustained major internal injuries in the fall and was in a lot of pain.
Doctor Julian Thompson and paramedic, Mike Nolan quickly gave him analgesia and procedural sedation before splinting his wrist, pelvis and left leg.
His internal injuries meant he needed to get to a major trauma hospital as soon as possible and was taken to Royal London Hospital in Whitechapel.
Mr Jones still receives treatment for his back and has lost 50 per cent use of his left arm, but had it not been for the quick pre-hospital medical treatment by the Air Ambulance team he may have been confined to a wheelchair for the rest of his life.
“Before my accident, I was aware of London’s Air Ambulance, but I didn't really appreciate it," said Mr Jones.
Now, despite an understandable fear of heights, the former policeman has decided that to raise funds for the charity he will abseil from a helipad 284 feet above London's skyline.
He hopes the abseil on Sunday will help him to conquer his fear and pay back the team who rescued him at London's Air Ambulance, stationed just down the road from where Mr Jones lives at RAF Northolt in West End Road, Ruislip.
