The longtime stylist for the Rolling Stones reveals the keys to his signature brand of well-tailored London nonchalance.

“A stylist is a bit like a sommelier. You consider the individual, you weigh up the particular occasion and its various ingredients and you suggest something suitable that would work.” So declares Mr William Gilchrist, bon viveur of Mayfair and rakishly debonair menswear stylist.

His keen eye and refined taste is highly sought-after. He’s Mr Oliver Spencer’s creative left hand, and he’s also the stylist for the Rolling Stones and Mr Jude Law. “I’ve been working with Jude for more than 20 years. We met on a magazine shoot in LA and we just got on,” says Mr Gilchrist. Keeping the Stones rolling after all these years is “very much a floating jigsaw puzzle: you’ve got to make sure the pieces can move but can fit together well.”

Now 50, Mr Gilchrist is a well-travelled free spirit who, though schooled in England, grew up in Kenya and Mauritius and worked as a fashion editor in Milan for L’Uomo Vogue and Arena magazines and then in New York for DETAILS before returning to the UK.

Here he takes us on a typically louche and Bohemian tour of his regular haunts in London’s W1 (a postcode that most wouldn’t normally tag as Boho) and along the way shares some style advice on how best to wear lightweight scarves and unstructured double-breasted tailoring.

I appreciate good design wherever I see it and the simplicity and utility of a Brompton bike is tough to beat. Literally. I often meet a friend here who drives an Aston Martin and I’m usually on my first espresso by the time he arrives. But I don’t work up a sweat because I’m never in a rush. I enjoy the journey. I like to go down life’s side streets. In my ideal world I’d be living on a sailboat somewhere near Naples, but pottering through Mayfair on a Brompton is my English version of that. If I’m stopping off at a gallery, I can fold it up and put it in the coat-check. And if I want to go out for a couple of drinks, or if it starts raining, it goes in the back of a cab, no problem. I have a special Brooks England saddle pouch in which I stash a silk scarf, a pair of sunglasses and a hip flask – all life’s essentials really.

I have NFO – no fixed office – and that’s the way I like it. When I began working, the option of not doing the same thing every day was very appealing, and it’s been my modus operandi ever since. I live within earshot of Lord’s cricket ground and cycle into town along the canal. I spend, on average, a day a week with Oliver Spencer at his design studio below his shop on Lamb’s Conduit Street in Holborn. I guess I have become his sounding board over the past 10 years and I enjoy the variety of our collaboration. I’m always looking, taking notes, keeping my eyes open, because in my opinion “if you don’t use it, you’ll lose it”. So I take my “office” with me: a trusty fountain pen in my buttonhole, a notebook in my jacket pocket and a digital camera tethered to my person by a lanyard. Because after three Martinis, cameras tend to go walkies.

Brent Pankhurst has cut my hair for many years. He now has a lovely barbershop on Newburgh Street, a cobbled little laneway just behind Carnaby Street in Soho. It has the feel of a members’ club. The rapport one builds up with one’s barber over time is very important. Brent and I get on well. He’s a lovely fellow: quite old school but with his own twist. He’s especially good at cutting an older gentleman’s hair. I turned 50 a few days ago, so Brent has a little less hair to chop than he used to, but it takes no less skill. I used to shave my beard off in the summer but years ago a very wonderful Italian lady asked me to keep it year-round. She has stayed in my heart and so I’ve kept the beard ever since.

The little arteries and arcades of Mayfair are still managing to hold on to some really interesting retailers – an antiques dealer next to a vintage watch shop next to an art gallery next to a gentleman’s outfitter. I love that you can walk down Savile Row and see the tailors at work in the basements. It’s choreographed theatre to a degree but it shows there is still incredible craftsmanship at work in London’s W1. At George Cleverley in the Royal Arcade they make bespoke shoes above the shop. And above that they have the “last room” – foot moulds of the great and good. It’s “dead man’s shoes” up there from floor to ceiling – a little macabre when you think about it – but it’s wonderful. George [Glasgow Senior], who runs the place, is a terrific character, full of amusing stories. He also stocks a very good whisky.

I’ve been going to George Club on Mount Street for years. It’s an especially cosy sanctuary in the winter and they know just how I like my vodka Martini in summer (stirred with a twist) and negroni in winter (a slice of grapefruit, rather than orange, gives it an edge). I come here to play backgammon – they have an excellent set: the counters are perfectly weighted. The game is a great blend of skill, chance and style. When I was growing up in Kenya, I once lost 43 times in a row to a great player, but he taught me well. I won my favourite board off a chap in Egypt years back when our truck broke down in his village. He was a very, very ungracious loser. One has to learn to be both a good loser and a good winner in life.

01 The utility of a scarf 

English weather is so changeable that a scarf is essential – even in summer. A silk scarf is an effective temperature regulator and also a useful transition piece. If you’ve been out all day but you have something on in the evening, chuck on a silk scarf and more often than not you’re good to go.

02 The versatility of a double-breasted jacket

For me an unstructured DB jacket is like a more polite denim jacket. I’m quite skinny and I feel the cold, so I like the wrapping factor: it feels like a cosy hug. I’ll often wear one with a T-shirt in summer and with a rollneck in winter.

03 The right choice of trousers 

I always get two pairs of trousers with every suit – one pleated wide-leg and one flat-fronted narrower leg. Then it’s really a case of the mood I’m in. But I never wear jeans. Despite having co-authored a book on denim, jeans are not for me. My version is a pair of Oliver Spencer work trousers, which are a bit like a chino.

04 The importance of washable fabrics 

I travel so much that I try to make sure that as much of my clothing as possible can go in the wash and that includes tailoring. Thus I can avoid the perils of the dry-cleaning vandals. I do not do dry cleaning.

05 The joy of bending the rules

I will always respect a host’s dress code. But I think one has to retain a sense of independence and individuality rather than just wear the uniform of the herd. I like good things and I respect the artisans who make them but I have a certain nonchalance to how I approach things. One can be elegant and stylish without having to adhere to the footnotes of some dead fool. So I say, feel free to bend the rules, including this one.