The City of London is halting a scheme that used recycling bins to track people as they walked by with their smartphones. The head of Renew London, which was behind the operation, wrote in an email, “I can confirm that we are not currently running any trials.”Quartz was the first to report on the tracking technology, installed in a dozen bins around London’s Square Mile. That story sparked an outcry of privacy concerns, with many Londoners expressing surprise at being monitored. The bins recorded a unique identification number for any electronic device in the area with Wi-Fi enabled.“We have already asked the firm concerned to stop this data collection immediately, and we have also taken the issue to the Information Commissioner’s Office,” the City of London said today in a statement. ”Irrespective of what’s technically possible, anything that happens like this on the streets needs to be done carefully, with the backing of an informed public.”Renew CEO Kaveh Memari wrote an open letter that sought to downplay what the bins could detect. “I’m afraid that, in the interest of a good headline and story, there has been an emphasis on style over substance that makes our technology trial slightly more interesting than it is,” he wrote.