Online numerical test followed by an assessment centre with four interviews - a competency interview with HR, business interview with consultants, a case study and presentation, and a group case study with the other interviewees.
The HR interview was fairly standard - tell me about a time when you had to persuade a group etc. The business interview was really a chat to assess your understanding of the industries wood mac focusses on and current market trends.
The case study was long - 1.5 hours preparation, followed by a 15 minute presentation and interview - I have interviewed at top tier management consultancies that don't do this.
The group interview was a very simple case study.