I was driving on the M1 South and positioned on the left lane approaching my exit at J24a at 50mph. I had barely noticed a swan in flight heading across the carriageway when it suddenly descended, impacting the edge of my windscreen and passenger mirror (which completely disintegrated). The accident left dents in my car's a-pillar front wing and door. Unfortunately the swan died, but fortunately instantly, as it's neck and head took full impact on the a-pillar and windscreen. I understand that later that morning, the police performed a rolling road block in order to move the remains of the swan from the left side of the motorway. On reflection, I feel somewhat lucky that the bird hit my car where it did. The level of debris and noise I experienced was in every way related to the huge size of an adult swan. I often think how much worse (for me) this could have been if it had collided with the centre of my windscreen! I am very fond of our natural wildlife, and in particular birds, and where I know swans tend to find one mate for life makes this episode something that will no doubt stay with me forever.