A pedestrian was seriously injured in a collision with a motorbike on the southern approach to Tower Bridge on Tuesday afternoon.
Emergency services were called to the scene at 2.48pm.
The air ambulance landed in Potters Fields Park and the pedestrian – a man in his early 30s – was taken to an east London hospital with head injuries. His condition is described as critical.
The motorcyclist stopped at the scene.
Anyone who witnessed the collision is asked to contact the Metropolitan Police on 020 8285 1574.
Tower Bridge remained closed to vehicles throughout Tuesday evening's rush hour, with significant delays to traffic on other river crossings and nearby streets.