“I’ve got a story for you,” the style director, Tina Gaudoin, tells me, smiling just a little sheepishly. She’s making me nervous, but I draw comfort from the fact that she isn’t likely to send me to a war zone as, without wanting to sound flippant, they tend not to have Fashion Weeks or edgy new designers, so how bad can this be? “You know how women are taught from an early age to dress for their shape?” she asks. And sure enough, too fat or too thin, buxom or flat-chested, women are deluged with advice about how to play up their strong suits and play down their weak ones. Between mums, magazines and makeovers by Trinny and Susannah it’s almost inescapable. “But men don’t really get any of that advice about dressing for their shape,” she continues. “And we’ve been talking about how sometimes you come into the office and you look great, you know, really great, but sometimes…” At this point, Tina trails off, bless her, so I finish her sentence. “And sometimes I look like dear old Hattie Jacques?”

We both knew I was exaggerating, but we also both knew that she had a point. Sometimes I look good: people tell me so. But sometimes I know I look portly. I look in the mirror and think, that’s all wrong, without understanding quite how. And so to be honest, while this wasn’t the most flattering assignment I’ve been sent on, it seemed to me that Tina’s suggestion – that I talk to the experts and get the stylists’ secrets and the tailors’ tricks – might make it one of the most useful features I’ve written. Useful for me, along with the countless men out there with – why not call a spade a trowel? – a bit of a belly.

Just how much I need that advice becomes clear when I speak to Richard Johnson, a senior menswear buyer at Harvey Nichols. We’re on the phone, and I’ve just stepped outside a pizza place in Wapping. Now I know I shouldn’t be eating pizza – a lesson brought home to me when I catch a glimpse of my reflection in the restaurant’s windows. Then Richard spells out the rules for a man with my physique. “By and large, round-neck T-shirts are less flattering – you’re better off distracting attention from your paunch with something like a V-neck or a polo shirt.” I am, of course, wearing a round-necked T-shirt, but Richard continues: “And while everyone can wear colours, really bright colours tend to be a mistake for your body type, as are T-shirts with strong printed graphics.” Oh deary me. My T-shirt is bright pink, with a dark pink image of a woman wielding a giant chainsaw emblazoned upon it. In other words, totally wrong.

A quick trip to Gap and a dark, monochrome V-neck later and I can see what he means. And trousers? “Well, don’t do a Simon Cowell,” he warns, “and always wear flat-fronted, because pleats just add to your size. But, at the same time, don’t go for a very low-rise cut – even though they’re fashionable.” Indeed, one key message everyone I talk to is keen to get across is that dressing flatteringly can involve eschewing clothes that might be wildly fashionable but that simply won’t suit you. So, just as not every woman is going to look good in a mini, not every fella is going to look good in skinny jeans, “because they just make some people look top-heavy”.

Why I love getting to grips with a fat man

Corpulent men are, funnier, less dominated by foppish styles and better in bed

• Don’t be in denial – even for the big guys, fit is everything

Background

• Dr Thomas Stuttaford: dysmorphophobia

• Men with ‘moobs’ swell queues for breast surgery

• Focus: Do my moobs look big in this?

• The curse of the man-boob

• Lavender oil may cause boys to develop breasts

Background

• Does my tum look big in this?

• Adonis complex?

• The curse of the man-boob

Background

• Men's health myths No 1: Well Man Clinics are a good idea

• Men's health myths No 2: you don’t use health services as much as women

• Men's health myths No 3: you should regularly examine your testicles

• Men’s health myths No 4: Viagra is the answer to erectile dysfunction

• Men’s health myths: men should see a doctor more

A chat with Graeme Fidler, the young designer making waves over at Aquascutum, gives me useful intelligence on coats. Blouson jackets? “Never!” Fidler assures me, which makes sense, as they can make even thin men look tubby. Besides, missing out on blousons is hardly a sacrifice. “Also avoid set-in sleeves with closely fitting armholes,” both of which, he tells me, are likely to make your waistline look large. “Raglan sleeves can work well,” says Fidler, referring to an Aquascutum classic coat, loose-sleeved so the old cavalry man could wield his sword. But then he points me in the direction of the Connolly, “a modern but classic peacoat” with that desirable “straight up and straight down” shape a chap like me needs to be aiming for clothes-wise, even if underneath it’s a different story.

So much for casual. For tailoring, I turn to Brioni. Where else? Brioni famously dressed both Daniel Craig and Pierce Brosnan as 007. But the 60-year-old brand – the best tailor in Italy, if not the world – has also dressed Tito, Pavarotti, John Wayne… important men, maybe great men, but not men famous for their slender figures. Today, Donato Liguori, Brioni’s top tailor in London, spends his days measuring up men of every size, shape and age and then comes up with the goods to make each and every one of them look their best. It can’t be easy, I suggest, to tell a captain of industry that his bottom is too big for a single-vented jacket (NB, they make your arse look bigger). “We are polite, but giving good advice is part of the service,” he explains. It’s vital for both the punter and the company, which doesn’t want to send out people looking anything less than amazing in those lovely, reassuringly expensive suits.

Also reassuring: Donato says I’m actually not that out of shape and puts me into a suit that’s more or less standard-sized. Handmade in Italy, it can be tweaked into a perfect fit here in Blighty (although Brioni makes suits from scratch for the oligarchs among us). “Now, look at me,” he says, opening up his jacket. “I, too, have a belly, but you cut a jacket a little tight, so that you can do up the central button just to arrive at a meeting, but then you unbutton it.” Then, with just a few pins, he works his magic on the jacket I’m wearing. Somehow, a nip at the back here and there broadens my chest, sharpens my silhouette and, hey presto, when I unbutton it, the paunch fades from view. Back at the office, I’m marvelling about this trick when a female colleague tells me, “Of course! None of my jackets buttons up properly.” But it was news to me, which illustrates Tina’s point: most men don’t know this stuff. But I also find myself pondering another of Donato’s pearls of wisdom. He describes how, when he’s discussing the various ways Brioni can enhance their figure, some clients seem reluctant even to look at themselves in the fitting-room mirror. “It is difficult. We can dress you and, of course, what we dress you in will make a big difference to how you look. But in the end, you have to like yourself.”