Reporter Michael Cockerell lifts the lid on the secret world of political lobbyists. The recent Cash for Questions affair put the business of parliamentary lobbying under the spotlight, but it highlighted only one aspect of the work of those who seek to influence the decisions of political leaders. While critics claim the practice is a danger to democracy, lobbyists maintain Westminster and Whitehall would grind to a halt without their work. This documentary shows lobbyists in action and reveals how effective they can be.