Sometimes summer throws us a style curveball when an unexpected colour or silhouette suddenly takes off, leaving you wondering how it happened.

Take chocolate brown, for starters. This rich, dark shade – definitely closer to an 80% cocoa blend than milk chocolate if we're talking food comparisons – dominated winter and spring.

woman in a brown dress with sunglasses and a straw bag, holding her chin.
M&S
Linen Cotton Blend Ruffle Maxi Dress, £46, Marks and Spencer

But did I expect it to survive into summer and become one of the season's key dress colours, and look perfectly chic and summer-ready with it? Absolutely not. And yet, here we are.

Linen Cotton Blend Ruffle Maxi Dress

Linen Cotton Blend Ruffle Maxi Dress

Linen Cotton Blend Ruffle Maxi Dress

Credit: M&S

One look at Marks & Spencer's new-in section today tells me the retailer – soon to make its London Fashion Week debut – is leading the charge with some of the best chocolate brown dresses on the high street.

Linen Cotton Blend Ruffle Maxi Dress

Linen Cotton Blend Ruffle Maxi Dress

Linen Cotton Blend Ruffle Maxi Dress

Credit: M&S

The £46 linen and cotton-blend ruffle maxi shown here, with its delicate cross-back straps, is one of the strongest. Though, I hasten to add, M&S also has a short-sleeved cotton shirt dress which, in the time it's taken me to write these words, has been selling out before my eyes.

Pure Cotton Pintuck Midi Shirt Dress

Pure Cotton Pintuck Midi Shirt Dress

Pure Cotton Pintuck Midi Shirt Dress

Then there's the playful brown-and-white polka-dot dress, also close to sold out, while M&S' premium Autograph collection offers a beautifully cut, dark chocolate viscose jersey dress with an intricately pintucked waist that works just as well in the office as it does for dinner. And this one is currently fully stocked.

Jersey Pintuck Maxi Dress

Jersey Pintuck Maxi Dress

Jersey Pintuck Maxi Dress

Credit: M&S

So why does chocolate brown work at the height of one of our hottest summers in 50 years? Simple. It looks polished and light, flatters more skin tones than black and pairs easily with summer's best cream, white, black, raffia, tan and metallic accessories.

In short, dark chocolate manages to be sophisticated, chic and summery at once, all you need to make it work now is a well chosen raffia bag, a gold or silver cuff, and you're golden.