Both outside and inside, the Barbican’s main auditorium feels less like a theatre than a rock arena on the night of a rare appearance by a legend. On the approach to the venue, desperate people offer unlikely sums of money to buy the tickets of those who have them, while, inside the hall, there is a high-pitched buzz of expectation from a surprisingly young audience.This atmosphere is generated by the casting of Benedict Cumberbatch in Hamlet. Although this absolutely is not one of those cases of a star condescending from Hollywood to do a spot of theatre – Cumberbatch has stage credits built up over 15 years. The success of Sherlock on television and an Oscar nomination for The Imitation Game have raised his profile to the level that this staging of Shakespeare’s most f