Turkish designer Bora Aksu (C) poses with models wearing his creations backstage.

Irish designer Paul Costelloe took fashionistas to a fantasy Paris for his spring collection as London Fashion Week got underway on Friday.

The 79-year-old mainly stuck to four pastel colours - blue, pink, yellow and green - for the line, called "Le ciel est bleu" (the sky is blue), which also introduced his new bridal line.

 Models present creations at the Paul Costelloe catwalk show during London Fashion Week.  

Against a painted backdrop of a Parisian boulevard and to the soundtrack of French songs, the designer opened the show with all-blue looks.

Models wore linen or check ensembles, tweed dresses and jackets and playful jacquard frocks. Floral prints and ruffles adorned some designs.

Costelloe described the line as "very young".

 Models present creations at the Bora Aksu catwalk show during London Fashion Week in London. 

"While London... in the late sixties, early seventies was the kind of fashion trendy capital, Paris was the couture and that was where I grew up in that couture environment and this all remained with me," he told Reuters.

"This collection kind of reflects that period."

Turkish-born designer Bora Aksu described his mother as his "greatest source of inspiration" as he paid tribute to her with his new collection of layered feminine looks with intricate embroidery.

 Models pose during the Paul Costelloe catwalk show during London Fashion Week.

Models wore tailored jackets, some with puffy or patterned shoulders and sleeves, as well lace and draped dresses. Florals adorned some of the designs.

Aksu used a colour palette of white, pale pink, yellow and blue but with bursts of bright red and navy.

London is the second leg of the month-long Spring-Summer 2025 catwalk calendar that began in New York and will also include fashion capitals Milan and Paris.

London Fashion Week, which celebrates its 40th anniversary this year, officially began on Thursday evening with shows and a party featuring singer Charli XCX to launch a new collection by high street retailer H&M.

It runs until Sept. 17 with Burberry, Erdem and Simone Rocha among the labels on the schedule.

The British Fashion Council (BFC), founded in 1983, launched its first London Fashion Week in 1984.

Over the decades, famous names including the late Alexander McQueen and Vivienne Westwood have wowed fashionistas with their creative visions at the London event.

 A model presents a creation at the Paul Costelloe catwalk show. 

"It's known for its entrepreneurship, it's known for its creativity, it's freedom of expression," BFC Chief Executive Caroline Rush told Reuters on Thursday.

"Those are the hallmarks of British fashion and that's what you're going to be seeing over the next five days at London Fashion Week." 

Reuters