It's the biggest day in the street's calendar: the Christmas lights switch-on. Cheryl Fernandez-Versini has been booked to push the button, but before she gets near it, a specialist team have got to make sure everything's in place for the big moment. The Metropolitan Police pickpocket team have an eventful weekend. There's a key job for the team building Crossrail, a brand new underground railway running underneath Oxford Street. We meet the personal shopper helping the Great British public dress better. A light has gone out at a landmark Oxford Street building. The problem is, it's 400 feet above the ground.