MEXICO CITY (New York Time)—The British government has notified Mexico that a handheld device widely used by the Mexican military and police to search for drugs and explosives may be ineffective, British officials said. Mexico’s National Defense Secretariat has spent more than $10 million to purchase hundreds of the detectors, similar to the “magic wands” in use in Iraq and Afghanistan, for its antidrug fight. Mexican military officials say the black plastic wands, known as the GT 200 (costing over $20,000 apiece) and manufactured by the British company Global Technical Ltd., are widely used nationwide at checkpoints to search for contraband inside vehicles as well as to canvass neighborhoods in drug hotspots for drug and weapons stash. According to media reports similar product used in Iraq and Afghanistan, the ADE 651 manufactured by ATSC Ltd., another British company, was considered ineffective. Controversy over the GT 200 has played out in recent months in Thailand, where the army has said it will continue to use them even though testing by government scientists found them far less effective than specially trained dogs. Human Rights Watch issued a statement in February calling on the Thai government to stop arresting people based on evidence gathered using the GT 200, which it said “performs worse than a roll of the dice.”