By Jonathan Davies

The founder of online fashion retailer Asos, Nick Robertson, has stepped down as chief executive.

Mr Robertson's resignation comes with immediate effect, but he will remain on the company's board as a non-executive director.

He started Asos 15 years ago at the height of the boom, and the retailer is now worth more than £6 billion.

But Asos has faced a difficult 18 months, battling falling profits and a huge warehouse fire in 2014 that forced it to suspend trading for a short period.

Nick Robertson will be replaced by Nick Beighton, who joined Asos as chief financial officer in 2009.

Asos chairman, Brian McBride, thanked and congratulated Mr Robertson for his achievements with Asos.

He said: “On behalf of everyone who works at Asos, I’d like to acknowledge Nick Robertson’s extraordinary achievement. His passion and vision have built a start-up into a world class company. We are all delighted that Nick will continue to contribute to the company that he started.”"