For electoral purposes, the UK is divided into constituencies, each of which returns one member to Parliament. As there are at present c. 630 constituencies, there is the same number of seats in the House of Commons. As the UK has a plurality or majority or 'first past the post'-system of voting (in contrast to Germany's proportional representation), the winner in a constituency is the one who has obtained the simple majority of votes. Thus he/she does not necessarily represent the majority in that constituency. The same applies to the winning party. It only has to have the simple majority to form the government. This also means that the government does not have to have the majority of the electorate. That voting system is very obvious in the seating arrangement of the House of Commons. The governing party sits opposite all the other parties. The two red lines on the floor may not be trespassed by either of the parties during debates.

The first two front benches on either side are occupied by ministers (or secretaries) of the government and the equivalent members of the Opposition (Shadow Cabinet) respectively. Backbenchers do not hold any special office and therefore sit on the back benches of the House of Commons.