The Hitchhiker's Guide to Britain's Elections

How It Works: 44 million registered voters are casting ballots for candidates in 649 of the 650 constituencies in the House of Commons (one constituency, Thirsk, has delayed its vote today after the death of a candidate).

Britain's second chamber in Parliament in the House of Lords, is an all-appointed body, so executive power rests on the vote for members of the Commons. The simple part: Britain has a "first past the post" system rather than proportional representation. So if members of one party win 326 or more seats, that party selects Britain's next Prime Minister.

Britain’s Election: The EA LiveBlog

In the 2005 General Election, Labour maintained power, albeit with a reduced majority, when it claimed 356 of 646 seats (so a margin of 66 over all other parties combined). Labour's leader at that time, however, was Tony Blair. He stepped down in 2007, replaced by long-time Chancellor of the Exchequer (and rival) Gordon Brown.


The other top party in Britain since the 1920s is the Conservative Party, now led by David Cameron. Given the recent difficulties of the Labour Party, and in particular Brown, the Tories should have walked to victory. However, Cameron has failed to impress many, and the party has not really established the distinctiveness of its polices.

Then the twist in 2010: Britain's "third party", the Liberal Democrats, suddenly burst onto the scene as an equal, rather than the supporting actor of the last 80+ years. The party's leader, Nick Clegg, was far more effective than Brown and Cameron in Britain's first-ever debate amongst candidates, and he has managed at least parity in the following two encounters. The Lib Dems also had their best post-1945 performance in the 2005 election, winning 62 seats, and they have a solid platform through their prominence in local government.

The outcome is that, for the first time since 1974, Britain faces the prospect that no party will win the 326 seats needed for a majority. The Conservatives have led in almost all opinion polls; however,  in all they have failed to reach the 40% level which is a general benchmark for control of the Commons. The most optimistic number-crunching in the run-up to the vote has the Tories at around 310-320 seats.

That outcome could shift today as voters shy away from the prospect of a coalition when they cast their ballots. However, if they switch from Lib Dem to Labour, that still will not produce a majority result; the Conservatives have to capture the last-minute deciders.

The prospect of a coalition adds to the important recognition that there are far more than three parties in this contest. Since Britain is not just England, any overview should take into account the Scottish Nationalist Party, which leads a minority government in Scotland (but was excluded from the candidates' debates over its firm objections and threat of court action), the Welsh nationalists Plaid Cymru, and the contending parties in Northern Ireland.

Then there are the Green Party; the UK Independence Party founded on getting Britain out of the European Union; the British Nationalist Party noted for its controversial views on race and ethnicity; Respect, launched in opposition to Britain's involvement in the 2003 Iraq War; smaller regional parties; and independent candidates.

Altogether parties beyond Conservative-Labour-Lib Dem won 30 seats in 2005.

Parties and Policies: The BBC has a handy portal offering an overview of positions and the manifestos of almost all parties involved in the 2010 election.

Watching the Numbers: A handy seat calculator can help you measure the likely outcomes as the percentages come in tonight. If you're impatient, you can judge the possibilities based on latest polls and on past elections.

And there is Britain's Nobel Prize-winning contribution to poll-gazing, the Swingometer, which will give an idea of how much of a shift in vote will be needed for the Conservatives to take power or, less likely, for Labour to retain it.

(The problem with the Swingometer is that even Britain's finest minds can't figure out how to make it 3-D. So while it can give you a measure of how the Conservatives can win in a straight fight with Labour --- the magic number is a 7% shift in votes --- it can't sort out the Lib Dem intervention.)

The Constituencies: For those of you now really getting into this, you can have a look at each of the 650 battlegrounds for the House of Commons.

For example, the home constitutency of EA is Birmingham Hall Green, which has the distinction of being a four-way marginal --- Labour, Lib Dem, Conservative, and Respect.