The legality of a proposal to widen police power in conducting drug tests on suspects has been called into question, with a human rights lawyer describing it as potentially unconstitutional. Michael Vidler said the proposal, put forward on Wednesday by the Action Committee Against Narcotics, constituted a "gross infringement of the protection of privacy", leaving open "a huge potential for abuse". The committee suggested that the police be given the power to conduct compulsory drug tests on the spot if they find drugs at a scene and the suspect shows signs of intoxication, an extension from the current practice where officers can only test if drugs are found on the person. Vidler said the "disproportionate" extension of police power, if implemented, would be the subject of an immediate constitutional challenge, which had a good chance of succeeding. Vidler called the proposal a "publicity gimmick by the government", and said it "wouldn't survive a constitutional challenge because it is not proportionate". Article 28 of the Basic Law stipulates that the freedom of Hong Kong residents is inviolable, and that arbitrary or unlawful search of the body of any resident "shall be prohibited". Responding to Vidler's criticism, a Security Bureau spokesman stressed that the proposals would be in line with the court's jurisprudence on human rights. He said that the drug-testing scheme could be justified when it was "rational and proportional to the problem", among other criteria. "So far, much has been done to tackle the drug problem, but the alarming rise in the [age of first-time drug users] suggests the need for examining the proposed scheme." The bureau's narcotics division serves as the committee's secretariat. But Vidler - the lawyer behind the court ruling that affirmed the right of transgender people to marry, and a member of the criminal law and procedure committee of the Law Society - cast doubt on the police being able to distinguish between a drugged and a drunk person. "Can you imagine a scenario where you innocently drink … and you have to undergo a drug test? "How many [police officers] in Hong Kong would be able to tell if someone is intoxicated on alcohol or intoxicated on cocaine, for example?" The scheme would merely become a "waste of taxpayers' money" as a result, he added. The committee has said that officers "with proper training" would do the tests, such as observing how a person answers simple questions. Currently, the only criminal offences related to drugs are trafficking and possession. The latter applied only to people carrying drugs, rather than those who had already consumed them, Vidler noted. "So what offences would they have committed [under the new proposal]?" The drug-testing proposal is undergoing a four-month public consultation.