The British government has two houses:
[ul][li]House of Commons: around 650 Members of Parliament (MPs), each representing a single constituency and each a member of a political party.[/li][li]House of Lords**: originally made up of unelected hereditary peers (whose position in the Lords passes on to their descendants), the current Labour government has sparked their replacement with life peers (whose position is not hereditary, and who in theory are selected without political bias for their experience).[/ul][/li]General elections are held every five years, although the governing party can call an election earlier. This is quite a common tactic; the government will often either hint at an imminent election to force the opposition to throw away their advertising budgets prematurely, or make some sweeping tax cuts and then be re-elected on a high of public opinion. Voters select one candidate in their constituency. The candidate with a simple majority wins (yes, a lot of people don’t like this system here for obvious reasons).
The three main parties are Labour, the Conservatives (aka Tories) and Liberal Democrats (aka Lib-Dems). Labour were traditionally the working class left-wing party, supporting public ownership but shying away from socialism. However, a swing further to the left in the early 1980s culminated in a crushing defeat in 1983 and ever since then the party has ‘modernised’ and ‘centralised’ to win the middle ground. In other words, it’s now very similar to the Democrats in the US – no more talk of public ownership or unilateralism. The MP leading the party, Tony Blair, is a very charismatic figure ready to change policies at the first whiff of a negative opinion poll. As a result, Labour are doing very nicely at the moment – well ahead in terms of seats in Parliament.
The Conservatives are traditionally the socially right-wing party, although Margaret Thatcher added economic liberalism in the 1980s (privatisation of everything in sight) to a heavy emphasis on ‘traditional’ morality. The economic liberalism was immensely popular in the 1980s, and the Conservatives enjoyed a spell in government from 1979 to 1997 with little opposition. However, once they lost Thatcher’s charismatic presence (her own fault; she alienated public and party with her stubbornness) and the economic boom ended, the Conservatives lost ground. They’re currently in a terrible shape, whipped in the 2001 election and riven by internal splits on whether they support or dislike European integration. They’re also in a leadership crisis, as the previous leader (William Hague) resigned after the election defeat. They’re the second largest party, but nowhere near as popular as they’re used to.
The Liberal Democrats are the small third party; they’re unlikely to form a government in the near future, but may hold the balance of power in the event of a close run race. Portraying themselves as young, dynamic and socially and economically liberal they steadily gain ground but often lose out due to the electoral system, often finishing in second place (in a winner-takes-all system).
The party winning the majority of seats in the Commons becomes the goverment. This is only effective if they have a majority over all the other parties; every vote is made by simple majority, so alliances between parties on certain issues are not unusual. The Conservatives usually ally with the small numbers of Ulster Unionists elected in Northern Ireland; the Lib-Dems sometimes ally with Labour on issues. Other parties in the Commons are mostly nationalists from Scotland (the Scottish National Party) or Wales (Plaid Cymru). Despite recent press, far-right parties don’t get a look-in at general elections.
Once in government, the winning party leader selects his or her Cabinet (committee of senior ministers responsible for the various ministries of the state) and announces a legislative programme. Bills (legislation prior to approval) are debated in the Commons and at select committees of MPs with particular experience or skills. Since a simple majority vote is pretty much all that’s required to turn a bill into an Act of Parliament, the use of a rigid disciplinary system is normal in ‘encouraging’ MPs to vote with the party line. Sometimes MPs vote against their party, but the party whips (MPs who enforce the party line) can make their lives hell. The government can also ‘encourage’ the local constituency party workers to put pressure on the MP; the local party has a major say in deciding which candidate can represent them in an election.
Bills are also scrutinised and debated in the Lords, although in practice their only real power is to delay bills, adding delays to the goverment’s legislative programme and jeopardising the amount of time available in the session (the part of the year the Houses of Parliament are working) for bills considered more critical by the government.
The opposition party (the second largest in the Commons in terms of number of MPs) can actually do very little to prevent legislation going through against a government that can effectively impose party discipline. Most opposition is through public opinion, party alliances or (most commonly) through MPs rebelling and voting against the party line.
I think this covers the basics. I hope.