The incident happened in Leesons Hill near Silverdale Road just before 12.20pm on May 25.
An ambulance crew and paramedics in fast response cars from London Ambulance Service attended.
The man was treated at the scene before taken to hospital where his condition is unknown.
We have contacted the Metropolitan Police for further information.
A spokesperson for London Ambulance Service said: “We were called at 12.18pm on Sunday (25 May) to reports of a person who had fallen in Leesons Road, Orpington.”
“We sent a number of resources including an ambulance crew and paramedics in fast response cars. We also dispatched London’s Air Ambulance.
“The first paramedic arrived in around five minutes. We treated a patient at the scene and took him by road to a major trauma centre as a priority.”
