At 74, Stephen Sondheim remains “available to his work, ever ready to amend and develop. As a result no two revivals are likely to sound the same. The small-bore Sweeney Todd at Trafalgar Square at the end of the month will be worlds apart from the full-orchestra Royal Opera House production, yet both are true to concept, as are many fringe and amateur stagings; there are 17 Sweeneys this summer across the UK and North America. For a man without a Broadway blockbuster or a pop-chart song, Sondheim has unrivalled diversity to his appeal.”