In 2011, I was cast in a production of Sweeney Todd: The Demon Barber of Fleet Street, the late American composer Stephen Sondheim’s 1987 musical. Sweeney Todd, about a murderous barber who slits the throats of his clients and his lovelorn landlord, Mrs Lovett, who bakes the bodies into pies and sells them, is one of the best and likely most popular of all Sondheim’s tricky, wondrous creations.

I remember that, in our first run-through of the show as a team, our director asked us to speak all the lines, including the songs. It’s certainly an appropriate way of approaching the work of musical theatre’s greatest lyricist, to read aloud his lyrics and appreciate their form. Sondheim’s music—at turns lilting and challenging and rich and deeply bleak in Sweeny Todd – sets his lyrics to a meter that can often conceal their meaning, their cleverness, the brilliant internal rhyming structure.