First Past the Post is the name for the electoral system used to elect Members of Parliament (MPs) to Westminster.
Former British colonies tend to use the same voting system as Westminster. Many, including Australia, New Zealand, Ireland, Cyprus, Malta and South Africa have since stopped. But the US, Canada, India, and many Caribbean and African states still do.
Most countries around the world use proportional voting systems – a party winning half the vote would win half the seats in parliament. But as India has over 800 million voters, most individual voters use First Past the Post (FPTP).
On election day, voters receive a ballot paper with a list of candidates. As only one MP will represent the area, each party only stands one candidate to choose from.
Voters usually put a cross next to their favourite candidate. But if they think their favourite has a low chance of winning, they may put a cross next to one they like with a better chance of winning.
During a General Election, 650 constituencies across the country each hold separate contests. To become an MP, a candidate needs the largest number of votes in their area. This means every MP has a different level of local support. In many areas, the majority of people will not have voted for their MP.
Even if millions of voters support the same party, if they are thinly spread out they may only get the largest number of votes in a couple of these contests. Tens of thousands of voters supporting the same party and living in the same area will end up with more MPs.
This means the number of MPs a party has in parliament rarely matches their popularity with the public.
This tends to generate two large parties, as small parties without a geographical base find it hard to win seats.
With a geographical base, parties that are small UK-wide can still do very well. This tends to mean that Westminster’s electoral system benefits nationalist parties. For instance, half of Scottish voters voted for the SNP in 2015, but the SNP won 95 percent of Scotland’s seats.
Westminster’s First Past the Post voting system usually allows parties to form a government on their own. But, these governments may only have the support of 35 percent (Labour 2005), a record low, or 37 percent (Conservative 2015) of the country.
Westminster’s voting system creates two sorts of areas. ‘Safe seats’, with such a low chance of changing hands that there is no point in campaigning, and ‘swing seats’, that could change hands.
As parties want to get as many MPs as possible, parties prioritise voters who might change their minds who live in swing seats. Parties design their manifestos to appeal to voters in swing seats, and spend the majority of their funds campaigning in them.
But, policies designed to appeal to voters in these seats may not help voters in the rest of the country. Voters who live in safe seats can feel ignored by politicians.
Many swing seats have two candidates where either could get elected. But some have more. The more candidates with a chance of getting elected the fewer votes the winner needs. In 2015 a candidate won the Belfast South election with only 9,560 votes, or 24.5% of the total, a record low.
Under Westminster’s First Past the Post system it is common for constituencies to elect MPs that more than half the voters didn’t want.
To combat this, voters try to second-guess the results. If a voter thinks their favourite candidate can’t win, they may vote for one with the best chance of stopping a candidate they dislike from winning.
As the number of MPs a party gets doesn’t match their level of support with the public, it can be hard for the public to hold the government to account.
More people can vote for a party’s candidates compared to the last election, but they can lose MPs. The reverse can also happen.
In 1951 and 1974 the party had the most MPs wasn’t the party that got the most votes from the public.
In New Zealand, the Labour Party won more votes than the National Party in 1978 and 1981, but the National Party remained the largest party and formed the government on both occasions.