Explosives alleged to have been handled by 'Big Spender' and his henchmen could have brought carnage, killing everyone in a 50-metre radius and maiming anyone within 100 metres, a court was told yesterday. An expert called to identify and contain the biggest batch of explosives seized in the SAR told the Court of First Instance that one gram of the 820kg haul was enough to blow a person's head off. A truck containing the explosives would have fragmented into shrapnel upon detonation, and if parked near a building would have caused the floors to collapse 'like a pack of cards'. Bystanders would have been cut down as sheets of glass from buildings showered the streets. Bomb disposal expert Dominic Brittain said the only thing needed for such a blast was a match. One reel of safety fuse would have allowed the bomber to be 'on the ferry to Macau' while chaos reigned behind him. Mr Brittain is an expert witness in the trial of Chan Sum-yau, 47, Wong Fung-kei, 44, and Lau Cheuk-fan, 32, who are each charged with possession of high explosives with intent to cause severe damage and injury. They have pleaded not guilty. Two of them were secretly filmed in January last year with 'Big Spender' Cheung Tsz-keung - who was executed in Guangzhou in December - handling boxes allegedly containing the explosives. The white powder was found to contain ammonium nitrate, fuel oil, woodchips and TNT. It was seized along with 1,997 detonators and two reels of safety fuse from a shack at the isolated border village of Ma Tso Lung, on January 17 last year. Mr Brittain said that after such an explosion 'there would be an extremely intense fireball that would set fire to anything in the area and cause further explosions from ruptured gas mains'. 'Anybody within a 50-metre diameter would have almost no chance of survival. In an explosion of this magnitude in a crowded city most of the casualties would be [caused by] glass raining down on the street. 'People would be killed by large sheets of glass raining down from 35 to 40 floors.' Mr Brittain said evidence suggested a bomber was intending to plant individual 2.5kg bags of explosives in several locations. One bag would probably kill everyone in a court room, he said. Chan was the owner of the house and was arrested there with Wong. Lau was arrested later at his home in Sai Kung. Traces of ammonium nitrate were found on the accused or their belongings, police say. The case continues before Mr Justice Peter Nguyen.