In seasons one to three, he was a Special Advisor to the Secretary of State for Social Affairs and Citizenship, and in season four he is a Policy Advisor to the Leader of the Opposition.
Ollie came straight out of Cambridge and into Government he's never had a real job. He thinks he knows what's going on but never actually does he's far too theoretical to really understand the the workings of PR and spin.
Ollie thinks he's cynical. He's not, Most of the department especially Cullen look at him with contempt but he still has his job because the ministers he works for have somehow got the impression that he can work miracles when his actions are really nothing but fluke. That said to give Ollie credit some of the ideas he has come up with are actually now adopted policies, so perhaps his approach does work after all.