I applied online. The process took 2 weeks. I interviewed at Mercer (Windsor, South West England, England) in Jun 2008
Interview
Phone interview followed by a full day onsite in Windsor. Quantitive and Verbal aptitude tests followed by two interviews with management in that office. I was asked to make a presentation to the HR lady. Group activity with other candidates. Overall it was a pleasant experience though I didn't quite come through with the level of detail expected on my mock presentation.