London is littered with good hair salons. But what about the great ones? In an industry where one misplaced snip can often ruin the whole experience (and your hair…), sorting the good from the bad from the brilliant can often be harder than it seems; especially if you haven’t already found the “one” that gets it just right.

The trouble is we tend to be creatures of habit when it comes to our choice of hairdresser. We don’t like change. It doesn’t matter if we’re happy with the end result, we still stick with the same person in the same barbers. Perhaps it’s time we buck the trend.

Enter Gielly Green. Founded by Shai Greenberg, the Marylebone salon had one simple promise: bring the best stylists and colourists into one space and give them the space to weave their magic.

Ten years after the launch of its first site, Gielly Green has now brought its gleaming shears to the City in the luxurious confines of the Four Seasons at Ten Trinity Square.

We ventured out to the salon to experience it for ourselves.

Ben’s experience:

It’s rare to wander into a salon knowing you’re about to have your haircut by a celebrity, but that’s exactly the status that Carmelo Guastella, men's grooming director at Gielly Green, has elevated to over his years of styling the rich and famous.

As a young boy, the budding stylist worked in a salon in Sicily at the age of 9; by 11 he was cutting hair. A move to London in 1999, was the beginning of his rise to stardom. By the mid 2000s, he was responsible for creating Ali G’s famous goatee (he remains good friends with Sacha Baron Cohen) and Robert Downey Jr’s facial hair for the Avengers films.

He’s the kind of guy who has transformed his craft into an art form – someone who can take one look at your barnet and know the missing ingredient. His actions aren’t just those of a guy snipping a few strands of hair, they carry the poise and grace of a grandmaster.

Let me be the first to tell you, though, he’s not impressed with what he’s seen on the heads of men in the City.

“If I’m totally honest, 90% of men in the City could do a much better job with their hair. I walk around the Square Mile during lunch and the amount of times I see a gent wearing a well-tailored suit and a Swiss watch, but a terrible cheap haircut is too many to count.”

He’s got a point. When it comes to our hair, a number of us are too quick to part with £15 in the nearest barbers – go in, come out with shorter hair, job done – but we’re often falling into the same old style mistakes that stop us looking our best.

That’s where Guastella comes in: “Your hair is a blank canvas. My job is to give you the tools to style your hair for next two to three months. You might not always wear your hair the same, but it’s about putting the right groundwork in place to have that flexibility.”

If I’m totally honest, 90% of men in the City could do a much better job with their hair

As he’s taking me through this process he’s working his way through my locks. Thankfully, I’m not the worst case he’s ever witnessed…

In tune with offering his clients different styling options, he recommends getting rid of my side parting and takes me through a new hair routine for the mornings (top tip: mix a little styling mousse or hair gel, to get a carefully styled ‘messy hair’ effect).

The result can be worn in a stylishly messy way, something a little more neat and tidy or just plain bed head. I’m not used to talking about my hair as having options, but it makes plenty of sense.

Be careful what you wish for: sitting here with the best ‘do I’ve had in years, a negroni in my hand and the expert advice of one of London’s top stylists. You’ll never go back to the barbers again.

I say exactly this to Guastella, and he smiles and shrugs: “If you’re going to spend all that money on how you look, why would you invest in a proper haircut? It makes no sense to me. If you want cheap, buy your suits from M&S to match your hair.”

I’ll take him at his word. See you in six weeks, Carmelo!

For more information, see giellygreen.co.uk

Jordan’s experience:

I’ve had my fair share of questionable experiences (think: zebra striped highlights; wonky layers; one haircut that was less pixie, more Paul McCartney circa 1960...), but at Gielly Green’s new City salon, it was clear from the word go – or, more precisely: “Hello, could we interest you in a cocktail?” – that this place ran in an entirely different league.

This petite, but stylish salon finds home in the heart of the Four Seasons at Ten Trinity Square. The usual order of service is a cocktail from the salon’s inventive drinks list, shortly followed by a smoothing head massage as Gielly Green’s fragrant shampoo and conditioner is run through and rinsed from your hair.

It was clear from the word go – or, more precisely: “Hello, could we interest you in a cocktail?” – that this place was different league

Once in front of the mirror, you’re in the expert hands of your stylist. That evening I had the pleasure of meeting Gigi Games, a senior stylist who was once part of the creative team at The Chapel in Islington. Quick to assess my face shape, morning routine (so important when you’re thinking about a new hairstyle) and hair condition, Games set to work snipping, styling and brushing out my side sweeping, flippy hair to create a middle parting with soft, bouncy curls.

It’s a new look, but one that’s quick and easy to recreate at home. The trick? Spray your Redken Triple 32 Take hairspray on wet hair before blowing out your waves for a style that’ll stick with you throughout the day. You’re welcome. But, don’t worry, you can thank Gigi Games for the hot tip in person when you book your next appointment at Gielly Green, Ten Trinity Square.

For more information, see giellygreen.co.uk