Mariinsky Ballet, Cinderella, 30 Aug-1 Sep Festival Theatre Formerly known as the Kirov, the great St Petersburg ballet troupe and o rchestra, under music director Valery Gergiev, give four performances of the new Cinderella created for them by Alexei Ratmansky, Russia's outstand ing new classical choreographer, former Bolshoi Ballet chief, and now Ame rican Ballet Theatre's resident genius. Prokofiev's score is full of fairy magic and ugly sister humour. (2hr 50m) Booking: www.eif.co.uk