Sadiq Khan has finally broken his silence on London’s knife crime crisis, telling LBC’s Theo Usherwood he hasn’t met any bereaved families. Khan did a broadcast interview today after days of silence as London’s 2018 murder toll reached 50 this week: there have been seven suspected murders since last Friday. As Guido reported earlier, Khan’s office had previously claimed he couldn’t speak out because of purdah rules. Sources said the mayor had been working from home this week. Bad look…