still on BBM – the four phone thefts at his school so far this term were all BlackBerrys. At the touch of a few buttons, a single BlackBerry message can be sent to the phone owner’s entire contacts book – several hundred people in some cases; on WhatsApp, the limit for a broadcast message is 50. But, for Bennett, Instagram is now a major social network. “Instagram is Facebook without parents,” he says. “Facebook has been taken over by the older generation. Once I saw my mum on Facebook, I deleted my account.” For families that may struggle to pay their heating bills this winter, the low price tag attached to buying and communicating on a BlackBerry retains its appeal. Unlimited BBM messages are available to anyone with a second-hand device and a £7-a-month deal from T-Mobile. But trust in the privacy of BBM’s system has been eroded. Part of the attraction to business people, revolutionaries, demonstrators and rioters was a belief that encrypted words sent over the company’s secure servers could not be traced back to their writers. Prosecutions after the riots put an end to that belief. Across town from Stockwell, outside the gates of a private school in well-heeled South Kensington, the older pupils all have Apple logos on their handsets. They all use WhatsApp. For many, BBM is a distant memory. “I still have a Blackberry, but I’m the only one,” says