Cobalt blue is the official colour of summer. If Marc Jacobs say so, it must be true – that’s the way fashion works.

It’s universally flattering, nice and summery and also, according to Isabelle Perrett and Yvonne Johnson in the book From Drab to Fab (natty name, I know): “It represents knowledge, decisiveness, honesty, calmness, dependability and stability – just what is needed to sooth nerves in times of recession.”

So there you go.

Also, on the tube yesterday, three girls on the row of five seats has cobalt blue bags. It’s an official trend!

3D 50 Denier Tights

£4.85, Love Colour

Coloured tights with all black outfits can look a little dated – especially when worn with matching accessories. However that doesn’t mean coloured tights are a no-no – far from it! Wear with other colours for contrast or with prints for a really bold look. Love Colour have tights in pretty much every colour imaginable and every denier, so if cobalt’s not your thing, fret not.

Pocket Dress

$9.50, Forever21

Even though the dollar/pound exchange rate is shit at the moment, there’s no getting around this dress being less expensive than a big fancy drink at Starbucks. As a Brit I’m unfamiliar with F21’s ways – maybe they’re like Primark and use sweatshops? I hope not. Anyway, nice big pockets and a flattering waistline – for less than a tenner? It’s the perfect summer dress.

Jolie Shimmery sequin leggings

£155, By Marlene Birger @ Net A Porter

Everyone needs sequin leggings in their life, especially extraordinarily expensive ones. This colour is so rich! One of the advantages of stupidly overpriced designer clothes is their access to so many amazing hues and dyes – you don’t get these peacock brights in your crappy budget store! I guess you could follow Net A Porter’s advice and wear these with a white t-shirt and blazer, but I’d rather wear with a sequinned bikini and stripper shoes and go for it.

Cobalt Blue Silky Full Pant Suit

$45, VonlenskaVintage @ Etsy

Nothing more to say than: yes!

Cobalt Blue Italian Square Toed Platform Heels

$55, VonlenskaVintage @ Etsy

The best thing about the 70s (after funk) was the shoes. I’m not a great one for flares and hotpants, but platforms I can get behind. Particularly when they’re made of weird ribbed fabric and have a curiously bendy heel. I’m not a great fan of a square toe, but somehow they work on vintage styles. Platforms are so mega comfy too – buy these before I do.

Vintage Cobalt Chain Purse in Leather

$32, BoroughVintage @ Etsy

The Etsy description says this bag has an ‘unusual glove silhouette’. I don’t see it, but I do see a nice bag. I guess the chain is pretty small but there’s room in the main compartment for at least keys, a cell phone, credit card and lipstick. What else do you need? Apart from a camera, change of shoes, deodorant, book, umbrella…