The UK general election is expected on May 6 2010, where around 45 million eligible voters will place a single X against the political party/candidate they want to represent them for up to 5 years.

With our current first past the post electoral vote system only the candidate with the most votes in each of the 650 constituency seats will be MPs despite the majority of those who become MPs not receiving at least 50% of the vote from their constituency (only 34% of MPs received 50% electoral support in the 2005 general election!).

In the 2005 general election, 19 million eligible voters cast ineffective votes (they did not get the candidate they voted for), that is ~70% of those who voted!

This results in a two party system (Labour or Conservative governments) with many smaller political parties including the Liberal Democrats, UKIP, Greens, BNP… being significantly under represented in parliament relative to the percentage of the popular vote they poll and a feeling among many British voters that their MP does not represent their views and in many safe seats an attitude of “what’s the point voting, my vote is wasted?”.

Prime Minister Gordon Brown plans to pass legislation committing a future government to a referendum on moving to an Alternative Vote System for Westminster elections by October 2011.

What is the Alternative Vote System?

With the alternative vote system the same 650 constituency boundaries are used as with the current first past the post vote system.

Voters again elect a single candidate from a list to represent them, but rather than placing an X against the ONE preferred candidate, voters rank candidates in order of preference with number 1 being their first choice, 2 their second choice…

If a single candidate polls 50% of the vote (50% number 1s) they would be elected as an MP just like the current first past the post vote system.

Where no candidate receives 50% of the vote the candidates who polled least have their 1 votes redistributed to their second choice candidates. This is repeated until one candidate receives over 50% of the vote.

Based on the 2005 general election results over 30% of seats will not be affected by the alternative vote system. So 70% of parliamentary seats could be affected by the alternative vote system, assuming similar voting patterns (which is unrealistic to assume).