Because of strong crosswind conditions at his planned destination the pilot diverted to a nearby strip which was aligned into the prevailing wind. Although the groundspeed was low during the approach the pilot elected to use full flap for landing. Shortly after touchdown the left wing lifted and the pilot was unable to apply full corrective aileron because his knee became jammed between the control column and the flap lever. The aircraft ran off the side of the strip and struck a fence. The fence was only 28 metres from the centre-line of the strip. In his efforts to apply full aileron the pilot had lifted his left foot from the appropriate rudder pedal, which probably increased the tendency of the aircraft to diverge to the right of the strip.