Traditionally the Conservative/Tory party was the party of the ruling classes, and traces it's history back to the Whigs of the C18th and C19th.
The Labour party was formed right on the cusp of the C20th, from various political groups like the Fabian Society, and the newly formed Trade Unions amongst others.
The Conservatives are similar to your Republicans, and Labour to the Democrats. As was stated, there is very little real difference between the two nowadays. Also the traditional supporters can't be catagorised so easily, our first women Pm came from the more traditional party for instance, and Labour now have a lot of supporters from the middle classes, and visa versa.
The Liberal Democrats are really a spent force, although historically they've played an important role in our political history. They would only really hold any sway if there was a hung parliament.
The UK Greens are very similar to yours.
I'm sure we as a forum, have many differing political views, which is probably illustrated by the fact that we have a Labour Member of Parliament, and yet we have a Conservative controlled council.
