Paul Costelloe, who has died aged 80, was an Irish fashion designer who was known for his outspokenness as much as for his simple yet elegant style; he designed dresses for Princess Diana for 14 years.
A stalwart at London Fashion Week, Costelloe designed for a wide range of modern (typically wealthy) women, “aged between 27 and 97”. Always aware of his Celtic heritage, he took inspiration from James Joyce’s Ulysses and the scrollwork of the Book of Kells; but his reach was international and his influences broad.
Working in luxurious fabrics, such as cashmere and satin, he made durable and practical clothes that nonetheless maintained their femininity. His colour palette could be paintbox primary – bright oranges, reds and yellows – or more subdued shades of beige, ivory and blue. He was capable, too, of old-school romance, with long, billowing gowns that recalled the Golden Age of Hollywood.
The combination of versatility and femininity made him popular with busy professional women. From 1983 until her death in 1997 he was a personal designer for Diana, Princess of Wales, commuting from his factory in Northern Island to Kensington Palace to do the fittings. Among the memorable outfits that he created for the Princess was the tuxedo suit she wore to the Pavarotti in the Park concert, which took place – in torrential rain – before an audience of 125,000 fans in Hyde Park.
Costelloe went on to dress Zara Tindall, who, as Zara Phillips, wore a metallic high-collared dress by the designer to the wedding of Kate Middleton and Prince William. The Duchess of Cambridge herself was a fan, although Costelloe professed his doubts as to her style credentials, telling the Irish press that she was “not as individual as Princess Diana”. In 2019 he made a similarly unfavourable comparison in relation to the Duchess of Sussex, observing: “She’s a touch of Diana, without the class.”
Though he was often charming in person, Costelloe had a ruthless streak and a talent for a caustic turn of phrase. Certain statements were often quoted back at him: mostly infamously his claim that “Irish women wouldn’t know style if it tottered up to them on ten-inch heels.” He later insisted that the remark had been misinterpreted. But the surrounding furore established his status as a celebrity in his own right.
In later years Irish newspapers prevailed upon him to provide fashion wisdom, whether on the vexed question of men in shorts (acceptable with a decent tan), or the dangers of deferring to the whims of celebrities (“A dress isn’t going to turn you into Sophia Loren or Gwyneth Paltrow overnight”).
All the while, Costelloe continued to turn out new collections for London Fashion Week, marking his 30th year on the LFW catwalk in 2014. The following year his range of products – by this time expanded to encompass homeware, menswear, eyewear and a bag collection – notched up sales of €21 million.
The youngest of seven children, Paul Costelloe was born in Dublin on June 27 1945 and grew up in a large house with tennis courts and stables. His mother Kay was an American from New York and his father William, who was from Limerick, owned a raincoat factory. From his father, Paul inherited an instinctive feel for the quality of fabrics that would serve him well throughout his life. Not being academic, he struggled at school and left Blackrock College aged 17.
He spent a year working in a pig slaughtering factory in Waterford before drifting into a year-long course at the Grafton Academy of Fashion Design in Dublin. Aged 19 he set off for Paris and joined the Chambre Syndicale de la Haute Couture. He spoke no French, struggled with drawing and was unable to sew on a button.
His fortunes changed when he was spotted by the designer Jacques Esterel, who hired him as a design assistant. After a couple of years in Paris he came to London to work for Marks & Spencer, which sent him for training in Milan. Subsequently he was retained by the Italian design house La Rinascente.
With the encouragement of his brother he moved to New York, appeared briefly in an Andy Warhol film and got a job as a messenger boy for an erotic magazine. However, his fashion career failed to ignite, and in his early thirties he returned to Ireland to set up his own label. Paul Costelloe Collections launched in 1979.
Two years later he was introduced to the US market through Bloomingdale’s, which stocked his clothes alongside those of the established Irish designer Sybil Connolly. His star continued to rise throughout the 1980s, and soon he was being mentioned in the same breath as internationally successful designers such as Margaret Howell and Jean Muir.
All three were known for their understated yet elegant approach to clothes and their love of high-quality fabrics: in Costelloe’s case, silk, Irish linen and Scottish and Irish tweed. To these he brought a touch of the avant-garde, making tweed jackets with velvet collars and Edwardian frock coats in tapestry florals. In 1989 he launched a lower-priced line called Dressage, billed by the Sunday Times as “a weekend look for the woman who wears Costelloe to work”.
The corporate sector took notice, and over the next two decades Costelloe undertook a string of commissions for high-profile companies, service providers and sports teams. He designed the uniform worn by British Airways staff from 1992 to 2004, restyled the uniform worn by Sainsbury’s employees, and developed the formal outfits for the Irish Olympic team competing at the 2004 Summer Games.
In 1999 Costelloe moved to London, where the company had a flagship store (opened in Knightsbridge in 1994). There, his customers included Sharon Stone and Heather Mills. Much of his inspiration came from cycling through Knightsbridge and up the King’s Road, and he preferred to study people’s outfits on planes or in shops rather than on the catwalk.
He often attributed his longevity in the fashion industry to financial necessity; he had seven children to support, all of whom were privately educated. But he also acknowledged that he had a continuing hunger for recognition: a hunger he put down to his early days as the overlooked youngest child in a large household.
Though he once said he would not encourage his children to enter into the fashion industry, all played a hand, on an ad hoc basis, in promoting Costelloe’s name. In 2010 his six sons turned out to model his four-button suits at London Fashion Week (“like a rugby team going into a particularly fragrant scrum”, as The Irish Independent put it).
His daughter, Jessica, also modelled for him and worked on the company’s social media presence. Costelloe’s most personal commission, in 2021, was to create a bespoke wedding gown for her. In tribute to her training as a mezzo-soprano, an embroidered treble clef ran down the sleeve.
Tall – 6ft 4in – and energetic, Costelloe would rattle off answers to interviewers’ questions at great speed, often wrapping up his sentences with a laugh. In his spare time he enjoyed painting watercolours, also at speed, and playing what he called “rubbish rugby”.
Paul Costelloe married Anne Cooper in 1981. They had seven children.
Paul Costelloe, born June 27 1945, died November 21 2025