Hmm... I'm not convinced by the class angle. I personally feel that people in power will generally act in whatever way they feel will keep them in power. That's all they want: to keep their jobs, their perks, their flows of private goodies.
Britain today looks like a very middle class society, with a native working class that has been reduced to more of an underemployed underclass, living on benefits on sink estates. Hence the Nu-Labour elites really are acting in the interests of the majority if they are acting in the interests of their socio-economic class. And are they doing what's best for the middle class majority? Hard to say and there's much disagreement.
But maybe they are acting in the interests of the upper-middle class or the upper class. Not too far fetched, certainly, but then we have to wonder why Nu-Labour got in power, and why they haven't been voted out if the electorate feels that they have been captured by rival class interests.
Imagine a political party that could guarantee economic growth and a "rising tide that lifts all boats", such that everyone from every class would be better off. They'd get voted in and they'd stay in power, because it would be in everyone's self-interest, and if people can do nothing else, they can recognise their own self-interest. However, that party doesn't exist and no one knows how to run the economy in such a way to guarantee prosperity for all. Even if a "working class" power ran the UK, there's no hard and fast guarantee that life would be better for working class people, not only because of the undoubted lure of corruption, but also because intending to make life better for one or more constituent groups does not necessarily ensure that outcome. That's a big lesson of Communism's failures in the 20th C, surely.
Anyway, based on what John said,
If you think Brown and co are corrupt and captured by upper (or whatever) class interests, you should want to limit their involvement in the economy.
If you think that the political system guarantees corrupt politicians captured by upper class interests, you should want to limit political manipulation of the economy, period, regardless of who is in power.
I don't think that there's any chance of having a revolution and making things fairer, because that just about never happens, certainly not if you're already in a democracy (unless we get to be citizens with a written constitution, at long last). Basically the best system is the system where the maximum amount of consent is required for a government to hold power, because that guarantees more public goods than private goods. Don't know of anythng superior to democracy in that regard.