As a result , British Waterways created a winding hole and installed a sanitary station in the old pillbox below the lock .
The lock became derelict in the 1950s and then formed the head of the navigation from the River Thames .
British Waterways created a winding hole and installed a sanitary station in the old pillbox below the lock .
The lock became derelict in the 1950s and then formed the head of the navigation from the River Thames .