A DETECTIVE sergeant who was dismissed from the police force after he testified in court for a friend without permission from his superiors must wait to learn if his appeal against the sacking is successful. Au Yeung Kwok-hing, 40, who won several commendations during his 19-year career, was dismissed with benefits after he told a US court he had been willing to flout police regulations to testify for his friend, Christopher Chau. His lawyer, Neville Sarony QC, told the Court of Appeal yesterday this was a 'petty breach of a petty regulation drafted by petty people'. Dismissal was too harsh a penalty and was inappropriate. At the most, he said, Mr Au Yeung's conduct was improper. His statement had arisen under pressure and had been a momentary lapse during strenuous cross-examination, Mr Sarony said. Appealing against a High Court judge's refusal to grant a judicial review of the police disciplinary penalty, Mr Sarony complained Mr Justice Mayo's decision was irrational and he had taken matters into account which were not relevant. He pointed out the force did not act immediately to discipline Mr Au Yeung, but gave him added and undercover responsibilities. That did not square with the Commissioner of Police's argument that Mr Au Yeung's continued presence was undesirable because he might violate regulations again. There was no suggestion his client had breached other regulations either before or after the impropriety, the QC said. Nicholas Cooney, for the Crown, argued dismissal was appropriate because Mr Au Yeung's conduct had amounted to 'severe misconduct'. 'A police officer must be seen to uphold the rules and regulations of his force. If he expects a citizen on the street to abide by the rules and regulations, as a police officer, it's his duty to show he's prepared to do the same,' he said. He said Mr Au Yeung had chosen to give evidence for his friend and he had volunteered the fact he was prepared to flout the regulations to help his friend; it was not forced out of him under cross-examination. The Court of Appeal reserved its decision.