North West Ambulance Service said they received a call at 8.31am on Monday November 25 that a man in his early 20s had fallen from a building in Victoria Street.
The North West Air Ambulance landed on the promenade close to the scene and paramedics are also in attendance.
It is understood the man was working on the roof of the Masonic Hall building.
A spokeswoman for North West Ambulance Service said he had suffered serious back and leg injuries, and paramedics were still at the scene.
More to follow...