A combination of hip hiking boots and mid-length skirts will reveal just a few inches of flesh at the top of the shin. Make the most of it before the cold banishes bare legs away until spring.

Fashion doesn’t always have practicality at its heart, but occasionally the two converge. This September is one of those times – and the autumn flash is one of those junctures.

Specifically the three inches of flesh at the top of the shin, the autumn flash is the part of the leg that you’re most likely to expose in September, that seasonal hinterland when it’s too warm for tights, but too cold for sandals; too warm for knee-high boots, but too cold for a hemline above the knee. The last shinbone unturned.

Evidence is mounting, from the bottom up. Hiking boots – not a typo – are the footwear of choice this autumn. Influenced by Prada and Gucci, sleek versions at Urban Outfitters and Tommy Jeans – and good old Blacks – are leading the high-street ramblers. Add a mid-length skirt, a hangover from summer – possibly tied at the waist, and ideally in tartan or tweed (Zara has a whole category of mid-length skirts through autumn) – and you have your flash.

The proverbial cherry, according to Grazia, Elle and some trial and error, is a pair of proper socks from Monki or Weekday, possibly doubled up for thickness, and ideally in a bright colour so as to differentiate yourself from actual hikers. Otherwise you get the gist: mid-length skirt, warm shoes. Weather depending, you can probably push this look through to November.

It’s impossible to ignore the flesh we choose to flash. Necklines and hemlines have long been a means of divining fashion’s place in the wider conversation. Consider, in the wake of Me Too, the last time you saw an A-lister’s sideboob on a red carpet? Or take the tabloid furore over Meghan Markle’s knees, recklessly flashed in the audience at the West End performance of Hamilton this week.

The autumn flash is benign by contrast, but is equally more than a strip of flesh. It marks the remnants of an extraordinary, if worrying, heatwave, is code for a new season, but moreover it’s the last hurrah for our legs before they vanish till spring.

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