L'Wren Scott was planning to close her business this week, a friend has revealed.

The designer, who had been in a relationship with Sir Mick Jagger since 2001, was found hanged in an apparent suicide at her New York apartment on Monday, and her friend, American fashion journalist Cathy Horyn, said she was going to announce the end of LS Fashion today.

Cathy wrote in a piece titled 'Memories of a Friend, a Teacher and a Fighter', in the New York Times newspaper: "I sent her text on March 12, checking in. She didn't reply, but that wasn't unusual.

"I learned since her death that she was planning to close her business, with an announcement on Wednesday. Still, as painful as the decision must have been for her, I wouldn't draw any conclusions from it about her state of mind. Nor should any credence be given to reports of a breakup with Mick. It's rubbish."

Cathy is mourning the loss of the designer and she is devastated the world has lost a wonderful person, who she describes as a "vital, intelligent woman".

She explained: "She was with friends on Sunday night, and, yes, they were deeply concerned about her, but, no, they didn't think she would do something so desperate. Not L'Wren.

Her death is inexplicable to me, and it makes me angry, too. Angry because it's the loss of a vital, intelligent woman, and angry because, this once, I don't want her to be a mystery to me."