Just noticed in the April 2012 edition (last issue) of Classic FM Magazine - that there is free entry to the - BMW LSO Open Air Classics Concert on 12th May 2012 at 6.30pm in Trafalgar Square, London (note - no glass or furniture allowed) -

The Principal Conductor is Valery Gergiev (if you have read Katherine Jenkins Autobiography - 'Time to Say Hello' you will note that Katherine was Awarded a new Award called 'The New Voices Award' by none other than The Maestro Valery Gergiev (who was given the task of deciding whom he thought was Worthy of receiving this Award - and He chose Katherine  - who was extremely proud to receive the Award in St Petersburg, Russia - sometime in 2007 I believe), So the BMW London Symphony Orchestra Open Air Classics - looks to be an Event not to be missed (especially as it is free entry).

Cheers, Les