Beatrice looked slim and lovely as ever in a pretty blue and indigo pattered dress by Erdem, who picked up the New Establishment award at the bash. The 24-year-old wore her hair loose around her shoulder and completed the look with black heels.
Prince Andrew's daughter gave a gong to departing British Fashion Council chairman Harold Tillman at the event, which was held at London's Savoy Theatre.
Lily, meanwhile, was tasked with presenting the Menswear Designer of the Year to Kim Jones of Louis Vuitton. The 27-year-old looked blooming lovely, showing off her sizeable baby bump in a midnight blue satin dress by ALC. She teamed the gorgeous dress with a Louis Vuitton clutch and a sleek up 'do.
The Smile singer is due to welcome her second baby next month with her husband, painting and decorating firm boss Sam Cooper. Their first child Ethel turned one on November 25, and Lily spent some time on her daughter's special day reliving her labour. ''This time a year ago I was in excruciating pain. It was worth it," she tweeted.
Meanwhile, Stella McCartney triumphed on Tuesday evening, scooping two prizes at the prestigious event.
The designer picked up Designer of the Year and Designer Brand, a double coup insiders have deemed well-deserved after her creations were put on an international stage with the GB kits that she created for the Olympics and Paralympics.
Alexa Chung picked up British Style, an award decided entirely by the public vote, for the third consecutive year.
And Sex and the City cobbler Manolo Blahnik , whose designs were immortalised by the hit TV show's main character Carrie Bradshaw, was honoured with the Outstanding Achievement in Fashion award.
Cara Delevingne, who has ruled the runways this year, appearing on the catwalk for major fashion houses from Burberry to Victoria's Secret, fittingly took home Best Model.