I was introduced to PwC Strategy by a headhunter. PwC Strategy is a strategy consultancy that is part of PwC UK. As such, the interview process was comparable to other strategy consultancies ie centred around business case studies.
I had a total of six interviews of which 3 with partners and 3 with senior managers. Each followed the same structure: introduction, CV-related questions to probe for values / abilities (eg "give me an example of when you where a leader of a team") with further drilling down, then a business case study and then an opportunity for me to ask questions.