In my opinion, any consultancy worth its name would charge no less than GBP 1000 per day. Indeed, this may vary depending upon the client, industry verticle, nature of work, location, reputation of the consultancy, etc.For instance, Accenture is currently involved in the merger of two banks (from an operational perspective) based in london and, I heard, they are charging GBP 1800 per day per consultant (which, in my view, is on the higher side considering the quality of their consultants, quality of their deliverables, current economic climate, not to mention that all they are doing is project management).