I saw a lot of reports in newspapers and cricinfo saying it was possible that if Clarke appealed, he would've been given out under the revised laws of Mankading.
But my doubt is since it was a clear case of the ball accidentally slipping from the bowler's arms during delivery stride, wouldn't it be a dead ball?
Law 23.4 (b)
(b) Either umpire shall call and signal Dead ball when:
(viii) the bowler drops the ball accidentally before delivery.
Can the pundits here throw more light on this?