I meet William Costelloe in the Paul Costelloe atelier on Great Portland Street, London. Sketches and watercolours are spread across his desk, and the atmosphere is somewhere between calm and chaos.
It's London Fashion Week, we're two days out from the show, and fittings are happening in the studio as we speak. The collection is very real and very close.
This is William’s first collection as Creative Director following the passing of his father, Paul. It’s a moment that carries such a weight – both of expectation and responsibility.
When I ask how he would describe Paul’s legacy, his answer is immediate.
"Firstly, Paul was my father, which was incredibly special… 34 years of being his son. One of seven children."
"He always wanted to make things in perfect quality, in the perfect shape. Make women feel and look good – and feel happy about what they’re wearing. Materials were always the most important."
William shares nostalgic anecdotes about growing up, going to his father’s fashion shows and being brought into meetings with Dunnes Stores, where afterwards they would reward themselves via soup and a toastie in Neary’s pub.
He was struck by how often people would approach his father with genuine warmth – emphasising it was not just the women who would sing his praises, but the men too.
An unsurprising story to me, having grown up in Dublin where no home is complete without a Paul Costelloe label (or ten) – whether they’re stamped on a mug in the kitchen, embroidered on bedding or stitched onto a blouse hanging in the wardrobe, they’re somewhere.
"That’s when I knew he wasn’t just a man," he says. "He was a great man. A talented man – and an artist." "I think that was his greatest legacy."
Irish heritage remains central to that legacy – and to William’s vision.
"He was so proud of being Irish," he says. "Presenting Irish materials and putting them on the global stage."
"Irish fabrics are the best fabrics in the world," he says firmly.
"They tailor like nothing else. My father was a champion of presenting those fabrics to the world – and that’s what I want to continue."
As we speak, William gestures toward the drawings in front of him. He trained at Chelsea School of Art, and the lineage is clear – each eerily similar to his father’s in technique, confident lines with washes of colour left behind by considered brushstrokes.
"I suppose we were both artists", he says. "That was really special."
He picks up his 'lucky brush’ and begins to paint, before continuing. "For years, he’d pass his drawings over for me to colour in – little floral prints, shading in where he wanted the shoulder pads. 'Bring that to life, William', he’d say."
Taking on a heritage brand in the wake of such a loss is no small thing, but for this family business, it feels more like an inherited instinct – or even destiny.
"He never gave me a brief," William adds. "He was always very like, just go with your gut. I suppose that’s why it feels like, kind of a natural progression."
We move out into the atelier, where the team are busy at work, and pieces are taking their final form ahead of the show. William lifts one jacket from the rail – a structured, classic silhouette with strong shoulders and large pockets.
"This is probably one of my favourite jackets," he says. "I think Paul would have loved this, because it’s very him." He pauses, then adds quietly, "When I saw it on for the first time, I did cry. It was just beautiful."
The collection, he explains, is "a celebration of tailoring – what tailoring is to the Paul Costelloe brand, to our DNA, and bringing it all back."
It opens with tailoring crafted from 100% Irish wools and tweeds by Magee Fabrics. Appliquéd florals, made from the same cloth, read as a nod to continuity – a legacy blossoming, rather than replaced.
"I really feel this is a new beginning," William says. "But still keeping what my father did so beautifully."
The collection stayed true to the core Paul Costelloe brand pillars – celebrating women, honouring heritage fabrics and championing classic tailoring – but there was a clear evolution in attitude. This wasn’t sentimentality; it was strength.
Silhouettes felt more structured, sharper and distinctly modern. Defined shoulders and clean lines gave the collection a striking feminine authority, while still respecting the house codes: Heritage fabrics were enlivened with subtle shimmering pinstripes. Corsetry was softened with silk and organza, wide pleated trousers brought movement, and oversized collars added presence without excess.
The palette centred around earth-toned tweeds, creams, chocolate and tan browns before shifting into black and charcoal.
William brings over a blouse featuring an in–house print combining William and Paul’s sketches. He holds it up, proudly.
"This was honestly probably our last kind of collaboration we did together, which was really special." He adds. "He spread his drawings everywhere around the house… it took a while to find the right ones."
I ask if he can point out which is which.
"So, this is Paul’s," he says, touching one illustrated figure. "He always drew my mother’s hair. She was his muse." Then, moving his finger across the fabric: "And this one is mine." He smiles.
It’s a detail – but it feels profoundly significant, if not symbolic of the collection; two hands, a father and a son, one legacy, one print.
I ask what is most important to preserve now that he is officially at the helm, and his answer is consistent.
"The quality of everything," he says. "Everything has to be beautifully made. I’ve got the best team here, and I believe in them – they make me look good, and they make the brand look good. It’s a team effort."
"Most importantly, I want every piece to last – whether it’s a mug, a handbag, a tailored jacket or some bedding," he says strongly.
I ask him a tough question: if Paul was sitting front row on Thursday, what might he have thought of the collection? He grins.
"He was hard to please," he says, smiling. "But in a fair way." "Each garment is a statement. It’s not just another garment. It’s been made to work together. I think he would have liked how concise the collection is..." William pauses.
"I think he’d be proud," he nods.
To close the show, a U2 track boomed through the Waldorf – a venue that was the backdrop for many of Paul’s collections – and when William stepped out to take his bow, the room rose to its feet. It wasn’t just applause, it was recognition.
From my teary-eyed vantage point, there was no question: Paul would have been proud, indeed.
