David Cameron: What you receive should depend on how you behave

There is an important by-product of the debate about spending cuts: a national conversation about what fairness means in terms of benefit-sharing and burden-sharing.

I think this is badly needed. For a long time in the UK, there have been two misconceptions about fairness that have had the effect of holding the poorest down, entrenching inequality and creating resentment.

Taking on these misconceptions and setting out what fairness really means is crucial to this coalition's plans to build a stronger and fairer society.

The first misconception is the idea that you can measure fairness by how much money you spend on welfare. Of course fairness means giving money to the poor, the sick and the vulnerable. That's why we have boosted child tax credits for the poorest. But if we want to make long-term progress on poverty, we have to recognise that a strategy overly centred on redistribution is doomed to fail.

That was the last government's mistake. They treated the fight against poverty as a numbers game – boosting the welfare bill to push people just above the poverty line.

But the whole picture of poverty is not contained in a snapshot income-distribution decile graph. It says nothing about the vital concept of mobility: the potential for people to get out of a lower decile – and the speed at which they can do so.

Neither does such an approach say anything about dependency: the extent to which people can get stuck in persistent, and frequently quite deep, poverty.

Fairness means helping people out of poverty, thinking not just about the cheque you give them, but the chance you offer them.

A strong family, a decent education, a good job – these are the real escape routes from poverty, so this government is doing all it can to support them, whether that's through early-years intervention or bringing in a pupil premium so children from the poor- est homes go to the best schools.

Most importantly, our welfare reforms are going to make sure work really pays for everyone.

The second misconception is the idea that measuring fairness is all about who receives state help. But this takes no account of where the money comes from.

But taking money from the man who trudges out to work long hours each day so the family next door can live a life on benefits without even thinking about work is not fair.

We need to think carefully about what we are asking people to pay – and we need to recognise that there are ways in which what you receive should depend on how you behave.

That is my obligation to all those who work so hard to pay their taxes. So if someone genuinely can't work, they must be supported – but if they can work but refuse to, we won't let them live off the hard work of others.

A crisis in our public finances and a coalition in our politics have given us our moment. We must use it to start a revolution in fairness; to get as close as we can to a country where everyone can get on and up in life.