London police finally understand why 80,000 phones disappeared from the city's streets last year. The answer involves budget cuts [non-paywalled source] that hollowed out British policing in the 2010s, the arrival of electric bikes that made theft easy, and a lucrative black market in China where stolen British phones retain full functionality. The Metropolitan Police discovered an industrial-scale operation in December when officers traced a woman's iPhone to a Heathrow warehouse on Christmas …