Chris Mason: Uncertainty over benefits changes could go on for some time yet

Arguments about benefits always revolve around a single concept: fairness.

There are timeless questions – who is deserving and who is not?

It provokes sharp opinions and so is among the sharpest of domestic political decisions a government ever has to make.

There is a direct if not immediate consequence of a decision taken in Westminster on the money in the pockets of millions of people, including many who have little or – perhaps and – are attempting to deal with physical or mental health issues.

I'm told that in the last week or so the Department of Work and Pensions has been deluged with the worried – benefits recipients and their families concerned that they may be impacted, without yet knowing the specifics of what the government planned.

It poses a question for the government and journalists alike.

How responsible is it for titbits of ministers' plans to dribble out over more than a week, without the full picture being clear, given the concentration of concern it was bound to provoke among those who feel reliant on the welfare they receive?

The government wants to set out its argument over several days and journalists want to find out what they are actually planning.

But the net consequence is a flurry of worry, some of it perhaps justified, some of it not.

Even now, after the announcement, the complexity of people's lives confronts a complex benefits system, now changing again.

It could be some time before people know how they may be affected and even longer before they actually are.

Advocates of the government's plans argue that it is entirely in keeping with Labour's traditions.

They point back to the beginnings of the trades union movement and contributory benefits schemes, where people broadly got back what they paid in.

They argue that the creeping normalisation of worklessness for some, including for many they believe could work and would benefit from working, is what they are seeking to take on here.

They hope that by insisting they will protect those with the most severe health conditions, who are deemed never able to work, they can persuade more of the merits and practicalities of nudging others back to work.

It is an argument they know they need to make, because others in the Labour movement feel this is deeply antithetical to everything they stand for.

A few other things are worth pointing out.

One of the key reasons that there is still a lot we don't know about the government's plans is that the assessment of the impact hasn't yet been published.

How many people are projected to receive fewer benefits? Who are they? Where are they? What are their circumstances?

Ministers insist they have to wait until the chancellor's Spring Statement in a week's time to address this because the independent Office for Budget Responsibility puts out its numbers then, and all of this is caught up in that.

But this adds to the sense of uncertainty.

What is becoming clear is hundreds of thousands of people will be affected by these changes, and the biggest component of changes for the taxpayer will come from changing the eligibility for the Personal Independence Payment.

And one other thing is worth a mention: none of this will actually cut the benefits bill – it will continue to rise, albeit not quite as quickly as it would otherwise have done.

Which poses yet another question: is the benefits system sustainable after these changes, or could this government or a future one conclude further cuts are necessary?