I applied through Linkedin.
After a few days, I received an email from an HR asking to have a quick chat about the candidacy.
During the first call, they were asking me routine questions like why I want to leave my company, why ASOS, what's my expected salary.
At the end of the call, we arranged a first technical Skype interview in approximately a week. During this technical interview I was asked iOS and programming-related questions in general and it lasted about one hour.
After the first technical interview, they sent me a home assignment on a Friday, to be completed by Monday, it consisted in the realization of a small app.
The next stage was the face to face interview at their offices. It was a one hour interview: in the first part they asked about my past job experiences, in the second part they gave me detailed feedback about my assignment and asking why did I do specific choices. The third part was a short technical interview in which they asked me iOS-related questions and more general computer science too.