William Costelloe’s debut is a balance of tribute and future growth

The Paul Costelloe brand has been a regular fixture on the London Fashion Week schedule since its inception more than 40 years ago, and this season, new creative director William Costelloe presented an emotional tribute to his late father, who passed away in November 2025, as well as showcasing his vision for the brand moving forward, rooted in the brand’s tailoring DNA.

William Costelloe, who has worked alongside his father for the past nine years, has been tasked with leading the development of all the brand’s collections moving forward and backstage he told FashionUnited that he believes the brand is poised for expansion, both in the UK, as well as Ireland, where the brand is already well known through its collaboration with Dunnes, and in the Asian market.

“This [season] was emotional, but also an exciting look towards the future,” said William Costelloe. “Tailoring is our goal, that’s our DNA, our heritage, and we feel we create exciting, beautiful silhouettes that all women can wear and feel proud in. It’s really keeping within my father’s legacy, but also pushing it further, by adding my own little twist.”

William Costelloe plans to expand Paul Costelloe brand internationally

The starting point for the collection was rooted in the fabrics, with 100 percent Irish wools and tweeds by Magee Fabrics, purchased by the late Paul Costelloe before his death, which William transformed into an exploration of modern tailoring. It was a collection driven by a play of proportions, with sculpted silhouettes featuring structured, exaggerated shoulders, voluminous sleeves and oversized collars, styled with wide pleated trousers and bubble skirts.

William added: “My father will always be my inspiration, and I miss him greatly. He purchased all the fabrics, it was kind of the last thing he was working on right till his death, and the collection is how I felt the fabric should be interpreted, which was actually a real joy to do, experimenting on new silhouettes for the brand moving forward.”

The fabrics weren’t the only tribute to his late father; William also added an exclusive in-house print utilising archival sketches, with the hand-drawn figures and architectural lines, described as a “shared language of tailoring and form,” designed to honour the brand’s legacy, while also evolving its vision of modern tailoring.

“This was kind of our last project together,” William expressed when discussing the sketch print. “I went through the archives of his drawings and then combined them with my own, and we made the most beautiful print in three different colourways. It was really exciting when it came out on the roll of silk and then seeing it looking so beautiful in the finale dress.”

Other highlights include tailored coats softened with silk and organza blouses, cashmere rib and cable-knit styles with exaggerated collars and shoulders, while other pieces featured hand-crafted sculpted florals crafted from wool or large bow-like embellishments.

The collection was also styled with numerous bags from the brand’s leather accessories line, which William said was intentional, as he wants to create “a relationship between the garments and the bags working together”.

When looking to the future, William added: “I want to really push the UK market. I know we’re already very big in Ireland, and I want to extend that into the UK. This is where I live and where I’m based. I would like shops here, and I want us to be in department stores.

“I’m also looking into the Asian market. I’m probably going to be doing Seoul Fashion Week in South Korea, as I feel like our DNA and our heritage relate beautifully to the Asian market, especially Korea, where the women dress so elegantly.”