Alexandra Shulman is to leave her position as editor-in-chief of British Vogue, a role she has held for more than 25 years.
"Although I have had months to acclimatize to the idea of leaving Vogue, it hasn't made the moment of announcing this any less sad," Shulman said in a story on the British Vogue website this morning.
"I have been incredibly privileged to have been able to look after such a great magazine for so long and even more to have worked with so many people over those years who have made the experience so interesting and rich," she added.
A successor has not yet been named.
Shulman started her career at Over-21 magazine, and worked for Tatler and the Sunday Telegraph, before joining Vogue as features editor in 1988. After a stint at GQ, she became editor of Vogue in 1992, and last year oversaw the title's centenary celebrations, which included a cover featuring the Duchess of Cambridge.
Nicholas Coleridge, managing director of parent company Condé Nast Britain, said on the Vogue website: "Alex has been the longest serving and most successful editor of Vogue in its 100-year history. She has edited the title for a quarter of its existence, through its period of highest ever circulation, and its simultaneous transformation into a global digital brand."
Shulman, who intends to leave in the summer, has not disclosed her next move, but said: "It was difficult to decide to leave but 25 years is a very long time and I am tremendously excited that I will now look forward into a different future."