Under the method, which evolved with the emergence of mass democracy in Britain in the 19th century, each of the 659 MPs in the House of Commons is directly elected by the voters in his or her respective geographical constituency.

The candidate that obtains more votes than any other, however many candidates there are and however narrow the victory, is the local lawmaker, and the losers get nothing.

Advocates praise the system as easy to understand, giving a bond between members of parliament and local people and creating strong governments.

But to critics — who have been trying to change the system for 120 years — first past the post is hugely flawed. On an individual constituency basis, it can end up with a majority of the electorate, whose votes are split among a number of different losing candidates, not being directly represented in parliament.

These “wasted votes” mean that those supporting a party that is weak in their area—for example the right-wing opposition Conservatives in a poor, former coalmining town, or a fringe party anywhere—have little incentive to vote.

It also heavily favours the bigger parties, which tend to be stronger in certain regions rather than having support spread evenly around the country.

At the last general election in 2001, Prime Minister Tony Blair’s ruling Labour Party won almost 63 percent of House of Commons seats with just 40.7 percent of the popular vote.

In contrast, the Liberal Democrats, who want a European-style proportional representation system, gained 18.3 percent of votes but only 7.8 percent of the seats.

In recent years, various proportional representation methods have been introduced to elect assemblies in Scotland, Wales and Northern Ireland, and for European Parliament polls.

But despite Blair taking power in 1997 with a promise to hold a referendum on the issue, first past the post remains stubbornly in place for general elections.