What is the easiest way to upgrade any look? A waistcoat: How to dress like a grown up with SHANE WATSON

Let’s not beat around the bush. I’ve never had much time for cardigans because – if I had to narrow it down – they seem a bit studied, like wearing a tie or a one-shoulder dress.

Of course, I admired Diane Keaton’s Annie Hall look and Kate Moss’s 2007 Glastonbury waistcoat, worn with nothing underneath and jeans.

But for me, the moment never came when it felt like a waistcoat was just what I needed.

Well, for many reasons it is now. Finally, a waistcoat doesn’t feel like an unnecessary addition that might make you look like a hotel concierge, but something flattering, cool, and most of all, useful.

The first reason I’m on the hunt for a waistcoat — and you might be too — is because they’re an instant perk for mid- to high-waisted, wide-leg pants.

Let’s not beat around the bush. I’ve never had much time for cardigans because – if I had to narrow it down – they seem a bit studied, like wearing a tie or a one-shoulder dress (photo Kate McKinnon)

A tailored four-button waistcoat in crisp, neutral-coloured cotton, such as Albary’s camel waistcoat (£35, albaray.co.uk), which falls just over the waistband of your trousers, is one of those pieces that make you feel like you’re have come out with a few new looks.

If you’re a T-shirt aficionado, a waistcoat over a plain white T-shirt, worn with tonal pants, is an instant office-friendly look in a way that a T-shirt and pants alone aren’t.

If you like going bare-armed, the waistcoat and trouser combo – Albary has matching camel trousers (£55) – is basically a tight sleeveless trouser suit and can be dressed up in a snap for the evening with earrings and shiny sandals.

Last but not least, tightly buttoned waistcoats over long-sleeved blouses, worn with wide trousers or flowing long skirts, look elegant both day and night and remain beautiful through autumn.

On this particular point, I like a waistcoat because it’s the next step up from a tank top — smarter, sharper, making your top half look neat and shows off your sleeves — and because they’re a perfect contrast to the looser, baggier pants that have made their entrance and are not going anywhere.

If you're a T-shirt lover, a waistcoat over a plain white T-shirt, worn with tonal pants, is an instant office-friendly look in a way that a T-shirt and pants alone aren't ( photo Blake Lively)

If you like T-shirts, a waistcoat over a plain white T-shirt, worn with tonal trousers, is an instant office-friendly look in a way that a T-shirt and trousers alone are not (pictured Blake Lively)

The first reason I'm on the hunt for a cardigan — and you might be too — is because they're an instant brightener for mid- to high-waisted, wide-leg pants (Photo: Leah Williamson)

The first reason I’m looking for a cardigan — and you might be too — is because they’re an instant spruce up for mid- to high-waisted, wide-leg pants (Photo: Leah Williamson)

I don’t want to wear a skimpy top; likewise I don’t want to look too baggy, and this way I can wear a boyfriend shirt or a floppy blouse and the fitted waistcoat on top will give me some definition.

It’s too early to throw on a smart jacket and trousers, so this is the lighter alternative – a little tailoring to tie it all together.

Hints

  • Keep buttons simple
  • Keep the length hip-grazing
  • Go for a V-neckline with four buttons
  • Avoid wide lapels

Mango has a beige pinstripe viscose waistcoat (€35.99, shop.mango.com) that you can now wear with matching trousers (€49.99).

This is a four-button suit with a V-neck (the only way to go) and two welt pockets, which is the maximum amount of detail you need.

Very important to keep your waistcoat plain, sharply fitted and largely made up.

Cardigans also solve the problem of what to do with your waistband: let a shirt plume hang over the top? Wear a belt? It’s always tricky.

The right-hand four-button waistcoat (three is too short) fits comfortably and only covers your waistband, and if you prefer a longer line, like Mango’s oversized brown waistcoat (£33, next.co.uk), it will covering your hips , too.

A classic black four-button waistcoat is the no-brainer investment to wear with cream trousers or denim or to match with black trousers; think of it as the new look of a tuxedo.

Try Massimo Dutti for black and pinstripe waistcoats (£69.95 and £89.95, massimodutti.com) or Jigsaw has a viscose hopsack weave style (£120, johnlewis.com).

I’m also eyeing one in dark navy blue wool from Autograph for Marks & Spencer (£65, marksand spencer.com) to wear with a men’s striped shirt and jeans in the Charlotte Rampling style circa 1974.

When fall rolls around you might be in the mood to add a jacket to make a three-piece suit, but for me that's a step too far (photo Vicky McClure)

When fall rolls around you might be in the mood to add a jacket to make a three-piece suit, but for me that’s a step too far (photo Vicky McClure)

Very important to keep your vest simple, sharply fitted and largely made up (photo Hayley Atwell)

Very important to keep your vest simple, sharply fitted and largely made up (photo Hayley Atwell)

Now that jeans are flared, baggy or at least bootcut again, they’re clamoring to be worn with a waistcoat. You immediately look chic.

Some things to avoid. A halter neck, lapels, all the pretty details. The texture of your cardigan is all-important: anything felty or ethnic is too relaxed for our purposes, anything silky is too entertaining for kids.

Cotton, viscose, wool, maybe a subtle tweed is the way to go, as are muted neutrals.

As fall rolls around, you might feel like adding a suit jacket to turn it into a three-piece suit, but that’s a step too far for me.

What will look great is a beige or brown wool waistcoat under a leather jacket or a dark wool waistcoat and pinstripe trousers. I can not wait.