Police jeopardised a man's chance of a fair trial by allowing a videotape of a drug raid to be destroyed, a judge ruled yesterday. Judge Wayne Wilson stopped a High Court trial before it began because of the action. 'It was not up to the arresting officer to decide what was important, and to allow the tape to be destroyed,' Judge Wilson said. 'This is a material irregularity which may undermine a fair trial. Therefore I will have this proceeding stayed,' he added. The police knew the drug bust last December 28 was being recorded by car-park security cameras. But after viewing the tape they kept its existence secret, the court heard. Six months later, a defence solicitor by chance noticed the cameras in the car-park. But by then the tape of the incident had been wiped blank. The police seized the tape moments after they arrested Mak Kwok-cheung, 23, during a drug raid. He claimed the police had beaten him up and planted heroin on him. The police claimed that Mr Mak was carrying the drugs when they arrested him. An arresting officer watched the tape of the 15-minute drug raid for a few minutes and decided there were 'no discoveries'. But instead of holding the tape as an exhibit, the police returned it to the management of the car-park and said it could be erased. No record was made by the police of its existence. 'It is unthinkable that the tape had been destroyed,' said Clive Grossman QC, for the defence. 'As a matter of probability it would have shown the defendant. It would have shown if he was carrying a bag, and it would have shown if he was assaulted.' Mr Grossman said he was 'extremely suspicious' of the actions of the police and said the criticism should be levelled directly at them. Judge Wilson ruled the defence had a right to see the tape. 'Here is what might have been an important piece of evidence,' he said. 'Its absence now hinders the defence from showing anything at all from it. It is akin to an important missing witness or an exhibit which might weaken the prosecution's case.