There’s a chance I wouldn’t be chatting to designer Mr Luke Walker if he’d gone for a beer 15 years ago. “It was 2005. Lanvin had launched its men’s line and Lucas Ossendrijver had just started,” the founder of new brand L.E.J tells me on the eve of its arrival at MR PORTER. “All of the guys on the menswear course were going to see him to interview. I remember walking in and a mate of mine had just met him and he was like, ‘I wouldn’t bother with that, mate. Waste of time.’ I said, ‘Oh, really? Shall we just go have a pint?’” Luckily, Mr Walker thought the better of it.

Three months into the internship that followed Mr Walker’s successful interview, Mr Ossendrijver asked him to skip his final year at Central Saint Martins and offered him a permanent job at the French house. “That experience was incredible because it was quite a new studio [and] it was independent,” he says, adding that it helped being surrounded by visionaries in the field. “Being in a fitting with Albar [Elbaz, former creative director of Lanvin] and… the love and the joy and the excitement and the passion and the ingenuity that the man injected into everything we did, you can’t help but absorb some of that and learn from it.”

That five-year stint schooled Mr Walker in the importance of quality materials, make and fit, but it was his next chapter as head of design at Dunhill that instilled a lesson in commerciality: how to cater to a sizeable existing customer base. “It might seem like a completely different role on the outside, but once you start to scrape the surface, it’s really about all the same things,” he says. “It’s about beautiful fabrics, it’s about beautiful construction, it’s about balance of texture and colour, but the expression just has to be a little more tempered.”

Around 2016, after working with some of the biggest names in British heritage (at Pringle and Paul Smith, to name but two) during a period in men’s fashion Mr Walker calls “the sartorial rebirth of the suit”, Mr Walker embarked on what would become a partnership with Drake’s, the English shirtmaker and haberdashery. “I’d just had three years of suits and ties and quite formal clothing, and I was just like, ‘I don’t want that anymore.’ I want to be comfortable, I want to be casual; I want to wear things with pockets,” he says.

“I had this image in my head of what I wanted my personal uniform to be, so I started looking around.” What he found was an awful lot of very well-made vintage shirts or modern reinterpretations thereof, but none of them were quite right. “I thought they were perhaps a little too… costume,” he explains. “I was used to going into Dunhill, Drake’s or even Turnbull & Asser and spending the best part of £200 on a formal shirt. That’s because I really admire the construction and the finesse of the stitching and the beauty of the cloth. I wanted exactly the same thing, but in a casual shirt.”

Which brings us right up to date: the launch of Mr Walker’s own brand, L.E.J, which hit MR PORTER’s shelves last week. The collection consists mainly of shirts (with a few choice pairs of trousers and pieces of outerwear thrown in) and takes inspiration from the strangest, most unexpected of sources: a secret stash of hand-drawn aeronautical plans his father painstakingly penned many years ago. All of it, it goes without saying, is made with a similarly exacting degree of precision and attention to detail.

“When I’m working, I really think about how I want something to be constructed,” he says. “What’s the most beautiful, pure, utilitarian way that it can be made? That’s informed by looking at a lot of old stuff and how that was done, because most of it was done not for beauty, but for practicality: using the edge of the fabric, not wasting any. It’s about making things function and not fall apart. Ironically, factories find things like that very difficult to do these days because it’s not part of their modern construction process.” Here, he goes into the nitty-gritty of how he made five of his favourite pieces.

This military-inspired selvedge chambray shirt – which is woven in Okayama, the heart of Japan’s denim trade – is proof of Mr Walker’s obsession with construction. “This is probably top of my list because of the architectural nature of the design,” he says. “I give the factory a real headache sometimes, because I say, ‘I do not want any glue fusing or interlining,’ as I like the clothes to move. I like them to breathe and grow and express themselves. That doesn’t happen with the glue; they become stiff. If you look at this shirt, it’s got a clean placket – basically there’s no stitching on it – it’s just the whole body of the shirt folded back and then the pockets are stitched through that fold, and what that does is give them a big old reinforcement when you’re using them, stuffing things in them, pulling at them and snagging them, they’re not a single layer of fabric as they usually would be, but two layers. That to me, really represents how I go about designing everything.”

“This is another one that I love for the – and here’s another designer cliché – juxtaposition,” Mr Walker says. “The origins of it are in workwear, there’s twin-needling on it, it’s got a huge pocket, you can easily fit an iPhone 10 supersize or whatever they’re called, you can get a Moleskine [notebook] in there. It’s not a refined construction, but it has been refined. It’s workwear but made in an English way. Then the silk I love, because it raises all of these questions about, should men be wearing silk? And why are men afraid to wear silk?

“I take a lot of inspiration from reading and if you read a lot of literature from the 1930s to the late 1950s, a lot of the time when the author is describing the characters, sometimes the guys are wearing silk shirts. We think of a shiny, drapey, what we might call a ‘feminine fabric’, but actually they mean this really rich, almost chunky canvas, quite dry, almost Oxford cloth. I think this is not what you expect when you think ‘silk shirt’, this is something else. And the fact that it’s a workwear shirt in silk, I love that juxtaposition and the fight between those two ideas.”

“I put this one in there, because it’s the first style, but also because of that navy linen, which is special for MR PORTER – I wish I had ordered more for me. When it came in, it was just so gorgeous. The colour is like a pool of ink and the white stitching on it is like diamonds among the coal, it’s just so rich and beautiful.

“Initially, the style was developed and cut in a heavier weight; it’s got a two-piece sleeve and it doesn’t have a traditional gauntlet (the bit above the sleeve on the cuff), the cuff is actually in the sleeve, so it’s more like a denim jacket construction. And that’s because I really see that piece, and the other pieces to an extent, as quite versatile.

“Sometimes I wear it tucked in, and I always wear it open at the collar because that’s just my style, but very often I’ll wear it as a jacket in the summer because it’s got those two big pockets. There’s versatility in a piece like this; I want guys to take it and wear it however they want and I’m not going to preach about how it should be worn. Why would you? Clothes are for the wearer.”

“Again, this is an architectural design. It’s very similar to the silk shirt in the sense that it has two pocket openings, and usually when one puts their hands in their pockets, you go through to a pocket bag, which is a separate piece of fabric cut from a different cloth. But here, there’s a semi-diagonal line that goes all the way up from the hem to the shoulder so it forms an elongated triangle: that is the facing stitch.

“That pocket opening is just an opening, and the pocket bag is actually formed by the facing. This is probably one of those things that I’ve thought of for too many hours and fought with the factory about for far too many days, but to me, it’s something that is really beautiful. It’s back to that point of simple construction, a lack of fuss going on inside, but actually the simplicity is really complicated to achieve. That’s just one of the reasons that I love it.”

“The fabric of these is another Japanese number. Essentially, it’s a cotton-twill, which you’d get with any old chinos, but this one is woven on an old shuttle loom, so it’s got the selvedge, which makes it quite special. Generally, these days, we only see selvedge on denims or chambrays, so it’s kind of unusual to be on a fabric of this sort.

“A lot of the details [the patches and reinforced belt loops, for example] are taken from overalls. I want them to be knackered, to be worn and abused. I want them to fray and fade, patched and covered in paint and oil and all of those things.

“It’s difficult to sell a guy something and say, ‘Please make this as knackered as you possibly can,’ because that’s not everybody’s taste, but if I had my way, everything would be worn until it was actually threadbare and that’s kind of why I use the name ‘work jean’ to be a little bit suggestive on that front.”