It is 10 years since the Child Support Agency (CSA) first came into existence with responsibility for collecting maintenance for children whose parents had split up.

But throughout its life the agency has been heavily criticised for inefficiency and ineffectiveness.

Former minister Frank Field is one of the leading critics of the CSA

The prime minister himself accused it of "failing" children and last year the government introduced sweeping reforms designed to make the CSA more accessible and responsive.

File on 4's Jenny Cuffe speaks to parents and insiders who say not enough has changed.

Months of delay

One woman she meets is Claire, who turned to the CSA last April after splitting up with the father of her four-year-old daughter.

She could not meet the cost of a mortgage and child care on her salary as a nurse and she thought her ex-partner, who is in regular employment on a good wage, should take financial responsibility.

She was told that her case would be dealt with under the new improved system, designed to get money flowing faster to children. But she immediately experienced delays:

"I was just told there had been a backlog of claims," she says.

"It was just awful from the beginning. I had no point of contact, no case officer. Every time I phoned up it would be a completely different person so I would have to explain the case all over to them again.

"I almost found myself apologising for ringing them and bothering them - it's just the way you are made to feel."

After eight weeks, the CSA said they had assessed her ex-partner's income and she could expect �74 maintenance a week from then on... a sum that would make all the difference to her household budget.

But by the time Claire did start getting maintenance, 10 months after her first contact with the CSA, her ex partner had claimed a drop in earnings and got the sum reduced to �53.

Errors admitted

Any error for somebody who is caught up in this situation is an error too many and we need to do more to address that Chief Executive, CSA

In his foreword to the annual accounts, the chief executive of the CSA Doug Smith says it has been a difficult year but he tells File on 4 that many new clients are now receiving a better service than before:

"Like any other large organisation we make errors," he says.

"Given the complexity of the many situations we're dealing with within the Child Support Agency, I think our level of error is low but, as ever, any error for somebody who is caught up in this situation is an error too many and we need to do more to address that."

However, the agency is coming under increasing political pressure.

In an interview for the programme, the former Labour pensions minister Frank Field, who is a member of the influential Public Accounts Committee, calls for Mr Smith's resignation and describes the CSA as "broken backed."

Stephen Webb, the Liberal Democrat spokesman for work and pensions says it should be scrapped.

"There are only so many times you can patch a tyre before it's worn out and you need to replace it," he says.

For the CSA, Doug Smith blames many of the problems on a new computer system being used by the agency and says this is being addressed in a way that will deliver improvements:

"The Child Support Agency is improving its performance on a year by year basis and it's providing a valuable service to many of the most disadvantaged people in our society," he says.

"Our expectation is that we'll continue to improve the level of service on the back of improvements to the computer as we go through the next few months and then for the next year"