‘She’s actively rude’: Rose Byrne on playing a mother cracking up in her taboo-busting new film

What if loving your child is destroying you and all you want to do is escape? That’s the nightmare the Oscar-nominated Byrne faces in If I Had Legs I’d Kick You. The star and its director reveal why backers were scaredIf I Had Legs I’d Kick You, for which Rose Byrne just won a Golden Globe and is Oscar-nominated for best actress, is unmistakably a horror film. And yet how can it be? It’s the story of a mother, Linda, with a very sick child. You never see the child, only the outlines of the anxious medics. You never find out what’s wrong with her, only that it involves a feeding tube. Linda is going steadily crazy, because who wouldn’t? On paper, this is a painful yet heartwarming tale of love and adversity. Instead, it is claustrophobic and vertiginous. It sometimes has the panic-attack surrealism of an anxiety dream, and other times is so real you can barely look directly at it. I’ve never seen the maternal condition drawn as a trip to the abyss. The only film I’ve see