Disagreeing with a Child Maintenance Service Decision

If you disagree with a decision the Child Maintenance Service (CMS) has made, for example, the income used in the calculation or number of overnight stays with the paying parent, then either parent has a right to appeal the decision. This section explains how the process works.

  • Either parent has a right to appeal a CMS decision this can be done by calling the CMS to request them to look at the decision again.

    CMS Contact number: 0800 171 2345

    During the call the CMS will, either;

    • Raise the action during the call or

    • Support the parent to complete this on the online portal during the call.

    Once the appeal has been requested, it will appear in ‘Track Changes’ on the portal, and the CMS will make a decision based on the evidence available.

    Both parents will be informed of the outcome.

    Good to know

    Although the CMS may verbally guide a parent through how to appeal using the online portal, there are certain important areas on the portal that must be completed correctly for the system to recognise the request as an appeal. It is advisable to not attempt this without support from the CMS or specialist advice services.

  • After reporting a change, you will have an opportunity to upload evidence via the online portal. Visit Navigating the online portal.

    Evidence must be in picture format (Word documents cannot be uploaded) and you can go back at a later date and upload additional evidence if needed.

    If you have asked the CMS to look at the decision via phone, you can still upload evidence on the portal.

    The CMS may ask for further evidence from both parents before reaching a decision.

  • If either parent disagrees with the outcome of the the initial appeal, you can ask the CMS, to look at the decision again. This is called a Mandatory Reconsideration.

    You must apply within 28 days of receiving the decision letter. If there is further evidence, you can upload this via the online portal.

    The CMS may request further evidence for either parent.

    Both parents will be informed of the decision.  The letter may be worded as supersession accepted or refusal to supersede.

  • If you disagree with the outcome of the Mandatory Reconsideration, the next step is to apply to First Tier Tribunals, managed by Her Majesty’s Court & Tribunal Service (HMCTS).

    • This must be completed within 30 days from date of mandatory reconsideration decision.

    • This is a formal legal process, separate from the CMS.

    • There are no costs involved in applying to First Tier Tribunal

    • You do not need a lawyer, you can represent yourself or appoint someone to act on your behalf.

    Support is available and varies across the UK.

    If you live in Scotland please visit One Parent Families Scotland

    You can contact also contact your local Citizens Advice Bureau :

    For further information on the Tribunal process (opens in new tab)

  • When completing the tribunal forms,

    • Stick to the facts of the decision you are appealing.

    • Provide clear, relevant evidence to support your case.

    • Both parents and the CMS will be requested to send evidence at certain stages.

    • All evidence sent to the tribunal service will be shared with all parties involved.

    • Either parent can request that personal information (such as address) is kept confidential.

Some of the language and terms used to describe child maintenance can be confusing so we’ve created a terminology page where we do our best to explain terms.