A320 First Officer reports the Captain attempting to turn off the runway after an auto land without turning off the auto pilots. A hard left turn results which is only arrested by quickly stopping the aircraft.

Narrative

After auto landing; the Captain was some what concerned about the performance of the auto pilots with respect to the landing. We both considered it to be satisfactory but he elected to do another one on our return flight. The landing was again satisfactory. The aircraft decelerated through 60 knots and Tower told us to turn left and contact ground. As we made the turn; I noticed that both auto pilots were still engaged. I immediately brought this to the Captain's attention. It was at this time that the aircraft veered extremely hard left toward toward the grass. We both applied maximum braking and came within inches of leaving the pavement. Both auto pilots were then turned off. We taxied to the gate without further incident. The Captain was absolutely certain that he had disconnected the auto pilots while still on the runway before turning off. We were concerned that we may have hit blue taxi lights and reported it to the Tower. After further inspection; no lights were damaged.