A telephone interview consisting of basic competencies (recorded) and then a group assessment which included motivation and questions related to Waitrose. Finally, an interview with the section manager with similar questions.
I applied online. The process took 2 weeks. I interviewed at Waitrose (London, England) in Nov 2016
Interview
Online exercise followed by Group exercise followed by one-on-one interview with manager. Not too strenuous. Helps if you are comfortable with public speaking, and work well in a group. Don't be too pushy in group exercise.