I'm a bit stuck on detail for this question for revision for my January mocks!
Outline four electoral systems used in the UK?
There are several different electoral systems currently being used in the UK. For elections to the House of Commons, the system of FPTP (First Past The Post) is used to elect MPs. This is also known as the ‘simple plurality system’ where the winning candidate in each of the 659 single member seats simply needs more votes than any other candidate, and not necessarily an overall majority of the total votes cast. The party winning the largest number of seats becomes the Government. Voters only have one vote and, because many votes are wasted on losing candidates, it can be said that this system is unfair. This voting system is not proportional (the % of votes cast nationally for a party is not equal to the % of seats it wins) and discriminates against third parties, unless their support is geographically concentrated, and so favours more of a two party system. The present Government won a majority of 67 seats in 2005, despite only winning 36% of the national vote.
The Scottish Parliament and Welsh Assembly both use a different system called AMS (Additional Member System). Each voter has two votes, one for the constituency MSP/MWA and the other for a party on a regional party list, where each party nominates a number of candidates for these ‘top up’ seats, and places them in order. The country is divided into a number of regions based on the population size and each region contains several constituencies. Individual constituency representatives are elected (called an MSP in the Scottish Parliament and a MWA in the Welsh Assembly). The total votes cast in each region, together with the seats gained in the constituency vote determines how many additional members the parties win as regional members, who are chosen from the lists based on the voter’s regional party vote. For example, if a party is entitled to three additional members then the first three candidates on its list are elected. In general, the more constituencies won outright by a party, the fewer top-up members will be elected. The aim of the system is to produce a more proportional outcome. In 2007, the effect of the system in Scotland was to make the SNP the largest party by a single seat. The SNP formed the new executive, though it has a minority of seats in the Scottish parliament, and is thus unable to introduce truly controversial legislation.
A third type of electoral system used in the UK is that used for electing a Member of the European Parliament, called the Regional Closed Party List System. This is a strict PR system, and England is split up into nine electoral regions, with Scotland and Wales each constituting a region. Voters do not vote for individual candidates, but rather simply for a party, and each region elects up to 11 MEPs, with party representation depending upon the proportion of votes cast for it in that region. The ballot paper lists the names of candidates for each party in an order of priority determined by the parties.The effect of the system is to ensure representation for smaller parties - such as UKIP and the Greens.
A fourth system is the Supplementary vote, used to elect the Mayor of London. Voters mark their ballot paper with their first (1) and second (2) preferences. The first preference votes are totalled for each candidate. The top two contest the 'final'. The second preferences for all the losing candidates, wherever they are cast for one of the two remaining candidates, are added to their totals. At the end of the process, the candidate with the greater number of first and second preference votes combined becomes mayor.
I hope this is helpful.