Many decisions made in the Houses of Parliament are made as a direct result of lobbying - the influencing of members' votes either by parliamentary colleagues, constituents or outside pressure groups.
Lobbying takes its name from the lobbies or hallways of Parliament where MPs and peers gather before and after debates in the Commons and Lords chambers.
Traditionally, people wishing to influence the opinions of MPs or peers have frequented the lobbies seeking to persuade members of the validity of a particular viewpoint.
Nowadays, the term lobbying often refers more specifically to the work of private companies known as lobbyists which are employed by organisations to represent their views to Parliament in a variety of ways - by arranging meetings, organising protests or providing briefing material.
MPs are also lobbied directly by their constituents, local businesses and campaign groups on many issues.