If you're passing through Leicester Square station tomorrow lunchtime you could be forgiven for doing an aural double take when your usual guitar, accordion or didgeridoo busker is replaced by an immaculate viola quartet from the London Symphony Orchestra. Don't worry, they're not down on their luck. It's all part of the build up to the Proms and LSO musicians will be dispatched all over London to give impromptu free performances in unexpected places in a 10 hour musical marathon. Enjoy!
