What to buy now, when the weather is hot and hazy but, in theory, the height of summer dressing has, surely, nearly been reached? There is very little point in investing in another white kaftan dress at this stage of the game. With the exception of a few sale bargains and odd holiday necessities, most other undoubtedly summer fashion purchases will now see a very short lifespan, demoted within weeks to the holidaywear section of the wardrobe in the spare bedroom.

You can always count on Queen Elizabeth to wear some vibrant hues
Getty Images

But there is an emerging trend with surprising longevity; brilliantly coloured clothing. The new neons are significantly tastier than their predecessors – think watermelon, lemon and lime, like a palette of delicious sorbets, rather than a case of dried-up highlighter pens.

VICTORIA BECKHAM
Getty Images

Victoria Beckham is wearing her pink lemonade fizz in the form of a neat cheesecloth midi dress. The Duchess of Sussex, in limoncello yellow, showed us how to formalise rave hues in structured silhouettes. Browns Fashion says zesty green, hot red and fruity purple have been its bestselling colours of the summer so far, with Dolce & Gabbana and Zimmerman providing its most popular bright dresses. Topshop has more than 50 sunny yellow dresses available to buy right now, accessed via a website duly doused in fluoro.

MEGHAN MARKLE
Getty Images

Jules Standish, a colour expert and author of How Not to Wear Black, notes the centuries of research into the effect colour has on the brain. “Bright colours trigger neurological responses, causing the glands to release feel-good hormones. As well as the emotions, there’s a physical effect, improving blood pressure and strengthening the nervous system. Sunlight (or lack of it) seems to be an important factor when deciding on colour preferences. When sunlight is abundant, there is a preference for vivid hues.” Ergo, a heatwave prompts a sudden mass affinity with wearing brights.

KATE MIDDLETON
Getty Images

Generation Z (born in the mid-Nineties to early Noughties) has claimed a particularly popular shade of Snapchat-logo yellow as ‘theirs’ this summer, but that hasn’t stopped the Duchess of Cambridge, Melania Trump and others not in the age bracket from giving it a go. The new shades are easier on the eye than those that came before, more flattering for all skin tones and simpler to style. Why not try Ganni’s luminous green polka-dot blouse (sounds hideous, looks heavenly) with pristine white sandals for a beautiful contrast? Made an effort to build up your holiday glow recently? Rejoice in showing it off with a Borgo de Nor (at boutique1.com) dress in an Aperol hue.

STINE GOYA
Getty Images

The best neons look as striking on Instagram as they do in real life. Designer Stine Goya has found her way to cult status of late, thanks to a collection of sweet pink and sour yellow dresses that have chimed with the mood of endless summer mocktails.

‘We’ve noticed our customers becoming bolder in their choice of prints and colour,’ she says. Up to 10 women tag the designer on Instagram every day, in pictures of themselves wearing her rainbow styles. ‘The most popular pieces in our latest collection were two statement pink dresses. If designing with a bright hue, I usually build it in among a muted colour palette, like dusty earth tones or pastels, that will either pair nicely or contrast.’

ALIA BHATT
Getty Images

Wearing even a splash of bold colour has an instant effect on your wellbeing. It’s ‘optimistic’ fashion, as Ditte Reffstrup, the Ganni creative director, puts it. “The colours in the collection evoke the uplifting mood that takes over when the sun comes out.”

GRACE CHEN
Getty Images

Overall, Day-Glo hasn’t looked this chic in ages. The way to wear it is in a grown-up power dress or sleek separates, with glossy-looking accessories. Satin, crepe and cady fabrics thirstily absorb the colour-rich dyes, meaning that the most vivid options, generally, are matte cotton day dresses or silk evening wear. Neon couldn’t have come further from its glow-stick roots.

One day, naturally, the sun might go away. But if you shop savvily (ie pick a trans-seasonal silk blouse rather than a dress that you won’t wear later with tights), the whole trend carries through to autumn, too.

PRADA
Getty Images

Miuccia Prada styled citrus brights with black and navy on her winter catwalk. Think how gorgeous that raspberry sherbet top might look, refashioned as a ‘pop of colour’ when layered with a navy, burgundy or camel wool coat?

Also, as Goya mentioned, you might not be a person who ever wants to go the full fluoro. Even the biggest colour explosions can be easily diffused with neutrals. Pick a bright top, and add white or beige to take away the tang. It’s the sartorial equivalent to dousing fruit in cream.