ding jinhui potted 12 reds and 12 blacks to rack up 96 points in break .
but chinese star screwed back for the blue instead of the black .
world no 3 ding realised what he had done and held his head in his hands .
he then started to giggle along with his first-round opponent mark davis .
ding would have pocketed £ 30,000 for maximum 147 break at the crucible .
world snooker championships taking place in sheffield .