Once you get to the actual interview it is structured, well briefed and fully competency based. I in addition was given the chance to profile myself as a person. The interview was preceded by an assessment centre focussing on technical project management skills using a case study in groups followed by an out brief to a panel. Getting to the point of interview is tricky, realms of paperwork and long communication gaps. My overall process - without security clearance - took 9 months. I had 2 follow on interviews with the programme lead and the BU director.