Appeals & Changes5 min read28 February 2025

Can Child Maintenance Be Backdated?

Find out whether you can claim backdated child maintenance payments and under what circumstances the CMS will consider backdating.

Is child maintenance backdated?

In general, child maintenance through the CMS is not backdated to the date of separation. Payments are calculated from the date the CMS opens a case - meaning the date your application is received and processed.

From what date does the CMS calculate payments?

The CMS starts calculating from the date they receive your application (or the date the case opens if the paying parent applies). You will not usually receive payments for the period before the application was made.

How far back can I claim child maintenance?

You cannot typically claim maintenance for periods before the CMS case was opened. If you separated years ago and have not yet applied to the CMS, you will not receive payments for those years.

Apply early. The sooner you apply to the CMS, the sooner your entitlement starts. Delays in applying mean lost maintenance that you cannot reclaim.

Can CMS payments be backdated due to CMS delays?

If the CMS itself causes significant delays in processing your case, you may be able to request that payments are backdated to your original application date rather than the date the case was formally opened. This is known as an administrative delay and you should raise it directly with the CMS.

What about arrears from a previous arrangement?

If the paying parent has missed payments under an existing CMS or CSA arrangement, those are treated as arrears rather than backdating. The CMS can pursue arrears, and they do not disappear when a child turns 16 or 20.

Private arrangements and backdating

If you had a private arrangement that was not honoured, a court may sometimes award backdated payments as part of a broader financial settlement - particularly if the paying parent was shown to have deliberately avoided paying. This requires court proceedings with a family solicitor.

Frequently Asked Questions

Can I claim child maintenance from years ago?
Not through the CMS. The CMS only applies from when a case is opened. For arrears from an existing case, the CMS can pursue those indefinitely.
What if I had a private agreement that wasn't paid?
A private agreement is not enforceable through the CMS. You would need to take court action. A solicitor can advise on whether this is viable in your situation.

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Disclaimer: This article provides general information only and is not legal or financial advice. Rules and rates can change - always verify with the official UK government website or seek professional advice.