Politics is about answering two questions:
1. What goals should society be trying to achieve?
2. What are the best policies for achieving these goals?
Regarding the first question, in a democracy it is answered by giving everybody a (theoretically) equal voice/vote and averaging what people want. And in any cohesive society, such as Britain, there is a rough consensus on what sort of society we want. Everyone wants the country to be prosperous, people to be happy and healthy, and free to strive to achieve what they want from their lives. (There’s disagreement over what level of income inequality is desirable, but even here there’s a consensus in practical terms: if the benefits system was much less generous, millions would face real hardship, and if it was much more generous, millions would refuse to work because their matieral desires had been satisfied; so the benefits system is bound to stay roughly as generous as it currently is.)
There is less consensus over the second question, although nearly everyone agrees with the general outlines: Britain is going to remain a capitalist market economy, with enterprises largely privately owned, and with allocation of scarce resources largely determined by the market (of course, vested interests will continue to attempt to persuade legislators to rig the market in their favour, and sometimes they will succeed). And as well as the private sector, Britain will continue to have a large state sector, delivering public services.
So you might think that politicians ought to concern themselves with answering these questions, especially the second (the first is largely the electorate’s job to answer). But, instead, they seem to answer a third:
3. What do I need to say and do to get elected and attain positions of power?
As I put it on Less Wrong recently: for large numbers of politicians — probably the majority — the question of whether a proposition is true doesn’t really interest them all that much. They are more interested in whether a proposition will win or lose them votes. If they think it’ll lose votes, they won’t agree with it, and most lack the intellectual curiousity to care whether it is true.
This appears to be the case with Tony Blair and David Cameron, to give to well-known politicians. And in a representative democracy, those representatives who get elected are going to be those who’re best at getting elected, and only co-incidently those who’re best at running the country.