It is strange that the government has chosen to trail a speech by Iain Duncan Smith on an issue popular with voters on the same day as good economic news. The Work and Pensions Secretary has already reached an agreement with Chancellor George Osborne that it is possible to cut a further £10 billion from the welfare bill (when he originally said he would block those cuts), and is now starting to prepare the ground for some of those cuts to take place. He knows that while the public supports further welfare cuts, the Lib Dems will not without a credible package which ensures the rich are paying more.

One of the proposals that Duncan Smith is flying as a kite today is limiting benefits paid to families with more than two children. He made clear on Radio 4 this morning that the limit would apply to parents having children in the future:

‘My view is that if you did this, you would start it for those who begin to have more than… essentially it’s about the amount of money that you pay to support how many children, and what is clear to the general public, and this is very clear to them, that they make decisions based on what they can afford for the number of children they have; that is the nature of what we all do.’

This is sensible: rather than hitting an existing family for a decision taken years ago to have a third or fourth child, the benefit cut would apply to couples considering whether they can afford another baby in the future.

But as this is simply a kite rather than a policy announcement, the Lib Dems are keeping their mouths shut about whether this could be part of the package that they will approve. One senior party source tells me: ‘It’s not government policy and we haven’t signed up for it.’ Whether it will end up in their agreed package in exchange for a new policy that ensures the rich bear the greatest burden remains to be seen.

UPDATE, 2.45pm: A source close to Nick Clegg gets in touch to underline that this is indeed kite-flying and that they are not at all taken with the idea. The source tells me:

‘This is just Tory kite-flying, like they did at their conference. The Liberal Democrats have not signed up to it and it is absolutely not Government policy. The Lib Dems aren’t keen on it at all. It doesn’t even save very much money as we’ve already introduced a benefits cap.’

Tags: Benefits, Iain Duncan Smith, UK politics, Welfare