This information should not be relied upon as legal or professional advice. Read the disclaimer.

Three child maintenance schemes have operated under the Child Support Act 1991—the 1993, 2003 and 2012 schemes.

The first two schemes are closed to new applicants and ongoing maintenance cases have been transferred to the current 2012 scheme. In 2018, the Department for Work and Pensions (DWP) announced it was bringing outstanding arrears on the first two schemes within the scope of a write off programme.

MPs are often approached by constituents regarding decisions made by the Child Maintenance Service (CMS) relating to the current statutory 2012 child maintenance scheme.

Calculating child maintenance, establishing parental responsibility and collecting and enforcing arrears can be complex areas. This page signposts key sources of information.

Northern Ireland

A similar, but separate, system operates in Northern Ireland. Information can be found on:

Child maintenance calculations (Great Britain)

The CMS has published a child maintenance calculator, taking into account declared taxable income, number of nights of shared care and the number of qualifying and other relevant children (e.g children from another relationship).

This is only an illustrative guide—other factors may need to be considered. Both the parent with care and non-resident parent may be eligible to request a variation or for notional income to be taken into account (see section 8 of the Library’s Calculations, variations and income). Overseas income and enforcing maintenance overseas are described in the Library’s briefing on the topic.

Why, and in what ways, has the statutory scheme changed since 1993? (GB)

The Library is often asked for the reasoning behind some of the changes between the three statutory child maintenance schemes that have existed since 1993.

The Library’s Calculations, variations and income (UK) addresses some of these questions, including why the:

  • Non-resident parent’s income is no longer considered in calculations
  • Threshold to trigger a recalculation is 25 percent on the 2012 scheme
  • “Lifestyle inconsistent with income” was removed as a ground for variation
  • “Notional income” was introduced as a part-replacement to the above in 2018

How effective is the CMS?

MPs often raise how effective the CMS have been compared to its predecessor, the Child Support Agency. Library briefings describe the:

What information can I find out about child maintenance in my constituency (GB)?

The DWP publishes some data at constituency level on stat-xplore, under the CMS tab.  A user guide has been published.

Stat-xplore data includes the:

  • Number of children subject to CMS arrangements
  • Shared care arrangements between parents
  • Proportion of CMS arrangements in the CMS Collect and Pay service that are in payment (that is, the paying parent paid some child maintenance)

Note that most CMS cases are categorised as Direct Pay, where the non-resident parent pays the parent with care directly without CMS involvement. The CMS does not track the timeliness/completeness of payment in Direct Pay cases, but did publish a survey of Direct Pay client experiences in 2016.

The monetary amount of child maintenance arrears at constituency level is not routinely published but may be obtained through a written question to the DWP.

Making a complaint or appeal (UK)

For England, Scotland and Wales:

The CMS should respond within 15 days of a formal complaint to either clear the complaint or agree how to investigate if it will take longer. An MP may contact the Parliamentary and Health Service Ombudsman once the usual complaints process, via the CMS and Independent Case Examiner, has been exhausted.

For Northern Ireland:

An individual may contact the Independent Case Examiner and NI Public Services Ombudsman, once they have exhausted the CMS complaints process.

Official CMS guidance (GB)

  • CMS Service guidance—on calculating payments, reviews, receiving payments, appointing someone else to manage a CMS case, variations and shared care.
  • Guidance for DWP decision makers on child maintenance. This is a detailed set of guidance on the 2012 system that sets out CMS policy and relevant legislation across all areas. Seven volumes set out maintenance calculations, income variations, the information-gathering powers of the CMS, reviews and appeals, collection and enforcement powers, and the evidence the CMS will accept.

Hard copy guides (GB)

The Child Poverty Action Group’s Annual Child Support Handbook.  

What organisations can provide advice? (UK)


The Commons Library does not intend the information in this article to address the specific circumstances of any particular individual. We have published it to support the work of MPs. You should not rely upon it as legal or professional advice, or as a substitute for it. We do not accept any liability whatsoever for any errors, omissions or misstatements contained herein. You should consult a suitably qualified professional if you require specific advice or information. Read our briefing for information about sources of legal advice and help.