Kate Middleton has changed her hairstyle again

This certainly wouldn't be the first time a busy 30-something mum-of-two has decided life is too short to spend hours styling long hair. Except this is no ordinary mum.

Ever since Kate Middleton first caught the Duke of Cambridge's eye at St Andrews in a see-through knitted dress, she's been all about the hair. 

Long, dark and shiny, styled into thick, bouncy curls that occasionally – very fleetingly – put one in mind of a well-bred cocker spaniel.

So this new hair cut – a good six inches off the overall length – is not just any hair cut. It's a Duchess of Cambridge hair cut. And as such of vital national importance. Because it signals a change of direction not only in the way we now view the duchess, but also in the way she sees herself.

For years Kate has seemed to be the perennial model of the girl-from-the-estate-next-door, just the right side of demure to charm mater but sufficiently sparky to rouse pater from his post-prandial nap.

The glossy long hair, the tasteful outfits, the nude heels and clear nail varnish – they've long been part of her signature look, designed to strike just the right note of benign neutrality. Lately, though, the duchess has been expanding her style repertoire. For this year's Chelsea Flower Show she wore her hair off her face, along with a dark green Rochas dress that, by her standards, was positively edgy.

At her sister's wedding she looked amazing in Alexander McQueen; and again for Trooping the Colour; and again at Ascot. For the opening of the V&A's new exhibition wing she even wore a bold Gucci mini dress, trimmed in racy black and red.

This polka-dot number we see here is the envy of every woman: Dolce & Gabbana, the epitome of sexy, self-assured Italian fashion. She's even ditched the nude heels, in favour of a much more relaxed – and on-trend – pair of block-heeled sandals. High heels would have been too much; this way she looks stylish but laid-back.

If there's one woman alive who has the figure to carry off couture, it's Kate. So it's nice to see her embracing a more fashionable look. That said, it's hard to wear S/S 2017 McQueen when your hair is channelling the Hunt Ball, circa 2003.