John Hutton has said he is looking at tearing up the legislative framework of the Child Support Agency.

The work and pensions secretary admitted again on Sunday that the Agency, charged with chasing up errant fathers' family support payments, was failing.

But he said critics were wrong to blame the staff or work of the organisation, because it is doing what the government and parliament has asked it to.

The prime minister has already pledged a fundamental review of the CSA after he described as institutionally incapable of improving its performance.

"I think we should look very carefully at the fundamental policy framework within which the CSA is working" Hutton told the BBC.

"I think, fundamentally, we are not going to solve this problem just by looking at the performance of the CSA.

"The whole structure for calculating liability, for example, which is incredibly complicated in the primary legislation - I think we need to look very carefully at all of that.

"People tend to focus on the CSA as an organisation and say that it hasn't done a very good job. Yes, they are right, it hasn't. But it is doing the job that parliament asked it to do.

"There has been lots of really good people working in the CSA, working really hard to help families, and they have found it impossible in the current framework to do their job properly.

"I think we do need now to make some big decisions about the future and what is the best way to support families who need this maintenance being paid. At the moment too many families are being let down."