Royal fashion: Kate Middleton shows diplomacy in Canada

Let's skip the debate over whether or not Duchess Kate is a style icon. She's not, by the way – but that misses the point. What she is, rather, is a fashion diplomat. During this, her first foreign tour, she has shown an impressive ability to use her wardrobe as a tool for doing what royals are supposed to do on foreign tours. Her clothes show respect, bring an emotional warmth that strengthens historic and strategic bonds, and send a positive message about the country and family she represents – not that the protesters in Quebec were necessarily taking any notice of that.

Canadian symbols have featured prominently in Kate's looks so far. Her arrival outfit was a navy lace dress – very chic, her best look so far – by the designer Erdem, who is Canadian-born but lives and works in London. A smart touch, to reference the historic links between Britain and Canada in a contemporary way. The red maple leaf hat was another respectful nod, and the diamond maple leaf brooch, which she borrowed from the Queen for the trip, served both as a mark of respect to Canada and a way of bringing the Queen into the conversation.

The fitted grey dress she wore on Friday was not as pretty as her other outfits, but even this was deliberate. The day would have been Diana, Princess of Wales's 50th birthday, so Kate chose a sombre dress by Catherine Walker, who was a favoured designer, friend and confidante of Diana. It was a classy thing to do: to put herself in the shadows a little, and shift the focus to Diana.

Kate's signature look is defined by a sleek, slender silhouette, simple colour, and permanently red-carpet-ready hair. Royals on tour need to be recognisable, and she is: she knows as well as any spin doctor the pitfalls of over-complicating the message. There is not a lot of flair in how she dresses. The fan bag and the sparkly shoes are eye-catching, but a rather obvious way of signifying glamour for evening events. But flair is not what her wardrobe is about. As a diplomat of dress, she is rather impressive.