It is an unlikely coupling: one of Britain’s most ambitious and maverick cinematic talents taking on the most popular work in the operatic repertoire. Sally Potter is putting the finishing touches to her new production of Carmen at English National Opera, due to open next Saturday. She surely has no undue concerns: the piece is just about impregnable, guaranteeing box office returns, plenty of spectacle and a happy audience humming its easy tunes deep into the night.

But Potter is worried all the same. We know exactly how worried she is. She has been keeping a blog during the rehearsal period, part of ENO’s pioneering mini-website devoted to the production. In one of the diary entries, she wakes up at four in the morning and, unable to get back to sleep, instantly makes a short and rather haunting film about her anxieties. It ends with her running a bath, hoping it will give her a “clearer view” of the task at hand.