He has specific responsibility for drugs and other policy areas which range from serious and organised crime through to public order and the Assets Recovery Agency.

Before taking up his post at the Home Office, Vernon was a Government Whip from June 2003. Previously, he was Parliamentary Private Secretary (PPS) to Tessa Jowell, Minister for Culture, Media and Sport and he was also PPS to Estelle Morris, when she was Secretary of State for Education. Vernon has been a Member of Parliament for Gedling in Nottinghamshire since June 1997.