The Australian designer Nicky Zimmermann has a surprisingly efficient litmus test for assessing whether a piece will be a hit or not: “We always say, ‘Can you dance in it?’” The dresses that fail to pass the test with flying colours have little chance of making it off the pattern-cutting table. “It’s important. More so than you might think,” she tells me. “There’s nothing like a too-tight armhole or a dress that makes you feel like you can’t move to ruin your day.”

Zimmermann, the Sydney-based brand that has dressed everyone from Beyoncé (who once caused mass hysteria when she popped into the brand’s boutique in East Hampton, New York, unannounced) to Katy Perry to Rihanna to the Princess of Wales, would know. It is