Started off online. You get some on line assessment: one for numerical logic and one for verbal reasoning. If you pass the threshold you get a competency based phone interview that lasts 45 minutes. If you pass the phone interview you get to go to an assessment centre at their expense in a fancy hotel around Europe (my case was Rome) for 2 days. Here they engage you in: a presentation of a business case, a 1:1 interview with the manager of the area you applied for, a group assessment about a fictional business case and a personality& creativity tests. There were 14 of us and they said that they received 6000 applications so I was pretty happy to have made it to that point!