Police were called to Eastbourne Pier around 4.10pm to a man who had fallen onto the beach.
Ambulance was called and the man was being treated for a serious head injury and he was flown to hospital in a life threatening condition.
The Health and Safety Executive has been informed as the man was working on the pier.
More top news
Forecast for tonight and tomorrow in the west
Forecast for tonight and tomorrow in the east
The private school teacher pleaded guilty to 11 incidents dating back to the 1970s and 1980s.