The future royal wore a trouser suit for her first official evening engagement with Prince Harry, ushering in a new kind of sartorial diplomacy

Last night, for her first official evening engagement with Prince Harry, Meghan Markle wore an Alexander McQueen trouser suit. It was slim-fitting, with cropped cigarette trousers, worn with very high stiletto heels and a cream dishabille blouse. The outfit was many things: very Saint Laurent’s Le Smoking, a bit Princess Diana, with a soupçon of Marlene Dietrich, even a hint of Carine Roitfeld (although Roitfeld probably wouldn’t have worn a blouse underneath the tux). What it was not was a Sandringham-appropriate boxy Catherine Walker skirt suit. It was notable because it didn’t feel like standard royal family dressing at all.

The royal family wrote the rule book on sartorial diplomacy. Usually, their approach is unambiguous. It is a gown embroidered with 2,091 shamrocks in Ireland; a Chanel tweed coat in Paris in the middle of Brexit; a dress by Polish designer Gosia Baczyńska at a garden party in Warsaw. It is the opposite of wearing a cult band T-shirt that only fellow devotees will recognise. The clothes are designed to speak of decency and propriety; the visual messages are clear enough to charm heads of state and reach the rest of us in the cheap seats as well.