David Cameron: I came into politics to do the right thing and make a difference

Real modernisation means agreeing with the Government when it does the right things. Let me give you an example from a debate I'm involved in right now: the Government's City Academy programme. There's a huge coalition building up to oppose the Government on Academies – Labour backbenchers, the teaching unions, many local education authorities, large parts of the educational establishment, influential press commentators.

It's incredibly tempting for an Opposition to score points by opposing Academies. But I've been to the Peckham Academy and the Harris City Technology College in Croydon and I simply ask myself these questions: Is it right to get businesses involved in funding education? Is it right to direct resources to inner-city areas where children from disadvantaged backgrounds have had a poor start in life? Is it right to give schools freedom to innovate and specialise?

My answer to all these questions is a resounding "yes". And that's why I won't oppose the Government on Academies. I will back them, and make as many constructive proposals as I can to improve them.

This relates to an argument you hear quite a lot in the Conservative Party these days. Some Conservatives say that what we need is "clear blue water" between ourselves and Labour.

I think that's crazy. I came into politics to do the right thing and make a difference. I didn't come into politics to engage in some positioning exercise.

Imagine if the doctrine of "clear blue water" applied in the commercial world. You're a supermarket chain up against Tesco, who's offering "good food at low prices". I know: we'll offer "bad food at high prices". It's no different in politics.