These Cos summer pieces are so good, my friends thought they were designer

It's no exaggeration to say that if I'm not at my desk at lunchtime, you'll probably find me shifting through the rails at Cos. I love the unfussy, minimalist silhouettes, which lean heavily into that cool Scandi girl fashion aesthetic despite it being a British brand.

Think deconstructed tailoring, billowing dresses and the perfect fit of jeans, all of which are easy to wear but have an expensive-looking edge.

In the past, I've nipped into Cos for an emergency date night dress, as well as investing in an oversized blazer for work that is now several years old (although you wouldn't know it from looking at the unbobbled and unfaded material).

Every summer I stock up on the summer dresses and plush cotton T-shirts, while its cashmere collection is second-to-none. Last winter, one friend, who couldn't stop stroking the arm of my jumper, whispered conspiratorially, “Where's it from?”. It took a whole evening – and several glasses of red wine – to finally convince her that it was indeed from Cos.

The same is true for a pair of buttery soft Mary Janes that I wore to a beauty breakfast. After learning that they weren't from a particular high-end designer, some fellow editors could be seen on their phones, discreetly adding them to basket. Given the luxe Cos Atelier collection even has it's own fashion show every year – this time in Rome for the spring/summer collection – the confusion is understandable.

And when fashion influencers you follow on Instagram, such as Sylvie Mus, Alexis Foreman and Danish twins Cecilie and Amalie Moosgaard Nielsen, are all wearing the brand, you know it needs to be on your radar. It's where I first spotted Cos' viral leather crescent-shaped handbag, which bore more than a passing resemblance to The Row's Banana Bag. I knew I had to have it.

It's true, Cos prices sit at the higher end of the high street spectrum, but if, like me, you're into shopping less but better, you'll be spoilt for choice. Another bonus is that Cos doesn't design clothing just for this season so you'll find yourself wearing its timeless pieces on repeat over the years and still feel amazing in them.

At last count, my starred ‘favourites’ featured over 30 pieces on the app. So it felt like the perfect time to head to the brand's store on Regent Street to try on the latest drops, so you don't have to.

The knitted maxi dress won me over for evening and I could see myself dressing it up with heels or wearing it with a simple pair of flat sandals on holiday. I also loved the cut of the denim jacket and plan to wear it on repeat to the office with a simple white vest top and slouchy trousers in summer.

Ready for a holiday season wardrobe upgrade? Welcome to my Cos Dressing Room Diary.

1. The slouchy jeans

Who doesn't love a pair of elasticated waist jeans? With its drawcord fastening and wide, full-length legs, these jeans are as comfortable as they are chic. Think athleisure when worn with a T-shirt or dress them up with a blazer for a more tailored look.

2. The throw-on denim dress

In a heatwave, there's nothing better for a sticky commute to work than a cocoon-shaped dress. This one re-imagines the traditional shirt dress with a cool exaggerated shape and midi length. Another bonus is the organic cotton it is made from, making this a sustainable classic, too. Comfortable and chic? Sign me up.

3. The viral bag

Cos has become famous for its cloud-like quilted bags, with every fashion influencer worth their salt propelling the crossbody and hand-held styles to cult status. I was immediately drawn to this micro-sized version in butter-soft leather, which is big enough to hold all the essentials for a night out: phone, keys, cardholder and lipstick.

4. The beach bar maxi dress

I always pack a maxi dress when I go on holiday and this one is so versatile. Wear yours with flat sandals for an alfresco lunch or heels for the evening. The square neckline and drop waist are especially flattering and even though the vertical pleats are on the sheer side, they are not so see-through as to be revealing. My favourite thing about this dress, though, is the sage-green colour.

5. The luxe earrings

I'm in my silver jewellery era right now and these earrings are serving up serious designer vibes. They're weighty enough to look expensive (hence the clip-on fastening) but not too heavy to feel overwhelming. The mismatched style adds interest, too.

6. The perfect summer dress

The ruched waist and open V-back with spaghetti straps seriously elevate this summer dress. The lightweight cotton material feels breezy on hot days and I'm always a fan of a dress with pockets. The way the skirt billows out from the waist gives it a slightly '50s feel, too.

7. The on-trend seashell necklace

Anything from the seabed is enjoying a moment right now – from seashells to pearls. As well as featuring a real freshwater pearl, I like that the knotted leather strap can be altered so it can be worn as a choker or a longer necklace depending on the outfit.

8. The versatile denim jacket

I love denim, especially in an indigo shade. I'm also a big fan of a boxy fit so this jacket ticked a lot of boxes. The oversized patch pockets elevate the look and the relaxed fit means it looks just as good when you sling it on over a dress as it does when paired with jeans for a double denim look. It's also the perfect transeasonal jacket as I can just as easily see myself wearing this over a jumper as I can a white T-shirt.

9. The suits-everyone little black dress

I have to admit, this dress was a complete surprise. I wouldn't normally opt for a mini dress, let alone an ‘80s style, but I couldn’t resist the bubble hem! The fluid shape means it really does flatter everyone, even those with a fuller bust like me. Fashion is meant to be fun and this screams parties, margaritas and dancing on tables with friends.

10. The must-have knitted co-ord

Stripes never go out of fashion, especially when they are part of a neutral palette. We predict you'll be reaching for this knitted co-ord with its earthy blend of tones – olive, grey, black and beige – for many summers to come. The tank top works just as well with denim as it does with the matching skirt so you can mix and match textures and styles.