Every time I see a woman wearing a pair of these trousers, I'm stopped in my tracks says SHANE WATSON. Here's where to get the best of this summery style

Every so often, you'll be going about your business and your eye will be snagged by something a stranger is wearing that makes you go, 'Now that's fresh'.

This is never a stop-you-in-your-tracks moment. It's not the same as the surge of joy you get from the sight of a pretty summer dress bouncing down the street, or the tug of nostalgia you feel when you see a young woman in a mini skirt a lot like one you owned when 19.

This feeling is better than all these, because you get it when you see a chic spin on something you already wear and could easily copy.

Actress Lily James in Ralph Lauren at the Wimbledon tennis championships in 2023

What's caught your eye is the newness and the freshness, but you might have something similar at the back of your wardrobe — and if you don't, you know you could find one on the High Street in a flash.

Last week, I had two of these lightning bolt reset moments simultaneously. Two women sitting outside a cafe in the sun: one was wearing a buttoned-up sand-coloured suede safari jacket and off-white jeans (very nice, but it looked expensive and we can probably do without a suede safari jacket).

The other was wearing a black blazer over a light beige sweater, and wide-legged cream trousers with a fine brown or black stripe (not close enough to see which) — and that was the firestarter.

Oh, striped trousers! Where have you been? The wearer looked like a modern-day Jackie Kennedy — and all because of her summery (but not so summery you couldn't carry them off in a shower), stripey trousers.

Brown or black on cream is this year's navy on cream, by the way — less nautical and it works better with all the summer black, of which there is a lot.

Model Gigi Hadid rocks pinstripes while stepping out in New York

In normal circumstances (and this is my number one fashion tip), I would have approached her, apologised for interrupting them and asked her where her trousers were from. (Note: it's too much to ask about more than one item: one looks like flattery, several looks like stalking.)

As it was, I was sailing past in a bus so we'll never know — I'd guess a few seasons old Ralph Lauren — but there are plenty of striped trousers in the shops, so replicating her look couldn't be easier.

Subtle and loose-legged is the key to getting these trousers right. Light ticking, not circus tent, is the effect we're after, and certainly not the thick black and red stripes we wore sprayed on in the Eighties.

The mood is easy, breezy and smart. A wide-legged style in cream with a skinny black stripe like Hush's Elissia (£75, hush-uk.com) or in sage, or brown or khaki, will give you the perfect summer 24-hour trouser.

There are striped trousers at either end of the smart casual scale, from Me+Em's wide-leg linen and lyocell blend, cream with a khaki stripe (£195, meandem.com), to a straight-leg drawstring style with a narrow double black stripe from & Other Stories (£75, stories.com).

Actress Katharine McPhee in pinstriped trousers at a polo event in Los Angeles

Don't be put off by drawstring waists. While they're more casual, so long as the waistband is covered by the hem of a sweater or a little black top, they're easily smartened up.

That said, the ones that have caught my eye are tailored, swaggery and Annie Hall-ish by Jaeger for Marks & Spencer (£125, marksandspencer.com) in ivory with a brown/black stripe.

Would I wear the matching jacket (£175)? I might, with a white T-shirt and flat tan sandals, to an air-conditioned office. Because the stripe is barely there, it's an easy summer look and looks better than a plain white suit.

Model Alessandra Ambrosio looks chic in striped trousers in Paris in 2023

Like most of us, I haven't worn striped trousers for years. And in case you're wondering, why now, the answer is because in a full-on trouser season you need options — and as long as the stripes are narrow and the cut is fitted on the hips, flared on the leg, stripes are naturally flattering.

But, surprisingly, that's not the main attraction. Stripes are a super-easy way of introducing pattern to an outfit, while keeping everything cool and simple.

Stripes don't feel like pattern, but they do break up plain clothes and block colours and give everything room to breathe. (The same goes for striped shirts, which are having a big moment: head to Zara for a selection of poplin stripes or With Nothing Underneath (withnothingunderneath.com) for the ultimate linen striped shirt).

Just don't wear the two together — that's instant pyjamas — and you're all set.