SB: Test screenings tend to be events that directors dislike, even fear, but you feel strongly they are useful.

CV: I think it’s absolutely 101 stuff that test screenings are useful and it’s got nothing to do with those questionnaires audiences fill in afterwards. What really matters is sitting in an audience in a preview theatre and experiencing the audience emotionally leave the film. It’s the most horrific thing. You have to be there to to feel it, 300 people disconnecting from a film.

Also, the thing that is always shocking is when you find your favourite scene, that you think is the funniest or most moving, will just drop like a stone at the screening and you realise it’s probably redundant. Then a scene that you thought wasn’t so great gets a huge reaction, it’s clearly doing something for the plot and the characters that you never imagined. As for who to invite, make sure it’s not your friends, they’ll say it’s marvellous. Instead, invite 40 or 50 people who are not friends and you’ll find it’s a fantastic way to find out what’s working and what’s not working in your film.