This is when you ask the CMS to look again if you think their initial calculation is wrong.

You should ask for a mandatory reconsideration if you think the CMS has used the wrong information in their calculation. For example, where they’ve:

• Made a mistake about the number of children your child’s other parent pays maintenance for
• Used the wrong income figures
• Not included all the days you or your child’s other parent care for your child

You can also ask for a mandatory reconsideration if you think your child’s other parent hasn’t been honest about their earnings. This will give you information on what income the CMS has recorded which might be useful if you appeal (see below). 

If you think your child’s other parent has income beyond their wages or self-employed earnings, or unearned income from capital worth over £2,500 a year, it’s better to ask for a variation (see below).

How to ask for a mandatory reconsideration

You have 1 month to ask for this from the date on your original calculation letter. You can do it in writing or by phone – there should be details for this on the letter. 

If you miss the 1 month deadline, your request will only be looked at in special circumstances – if you were ill or dealing with a family emergency, for example. If it’s too late to apply for a mandatory reconsideration, you can ask for a supersession instead.

If the CMS agrees with your request, they’ll calculate the amount again. If they decide you should be getting more child maintenance, you should also be paid the money you’ve missed out on since the original calculation.

Tip: always keep a written record of your communications with the CMS. If you talk to someone on the phone, it’s a good idea to follow it up with a letter or email to put things in writing.

If circumstances have changed and you think the maintenance amount needs recalculating, ask for a supersession. Either parent can do this at any time. For example, you could ask for a supersession if your child is staying over with their other parent less, or their other parent has a new job and is earning more money. 

How to ask for a supersession

You can apply any time online or by phoning 0800 171 2345. If the CMS decides you should be getting more child maintenance, you should also be paid the money you’ve missed out on since the original calculation.

Tip: always keep a written record of your communications with the CMS. If you talk to someone on the phone, it’s a good idea to follow it up with a letter or email to put things in writing.

If you want the CMS to take into account types of income that aren’t typically included in their calculation, you can ask for a variation.

You can do this if you think your child’s other parent has income or assets they’ve haven’t told the CMS about. For example, you might think your child’s other parent is using self-employment or is paying too much into their pension to make their salary look artificially low. The CMS won’t automatically look at these things in its initial calculation, but you can ask it to – especially if you think it might affect how much maintenance you get.

How to ask for a variation

You can apply any time online or by phoning 0800 171 2345. If you call, you may be sent a form to fill in. Make sure to keep a note of who you speak to and what you say.

When you apply for a variation, the CMS will expect you to prove the facts. They don’t usually carry out a detailed investigation. So you’ll need to give as much information as you can and use all the grounds you think apply.

There are 4 reasons (or grounds) that can be used for a variation. You have to say clearly which of these your request falls under. They overlap and you can use as many as you think are relevant.

The 4 grounds for a variation

1. Earned income – if you think your child’s other parent is earning more than £100 a week (before tax and National Insurance) from employment, self-employment or a pension – but they’re only paying £7 per week or nothing (nil or flat rate) and meet certain other conditions. It’s complicated, so if you want to know more, please talk to us
   
2. Unearned income – if you think your child’s other parent earns more than £2,500 a year from things like rental income from property, savings, shares or other investments (unearned income)
3. Assets – if your child’s other parent owns things with high value like stocks, shares, money or a second home. This doesn’t include certain things like business assets or the home they live in – and the value of a single asset must be at least £31,250
4. Diversion of income – if you think your child’s other parent is controlling their own income to appear less well off than they are – for example, if they’re self-employed or run their own business. You might use diversion of income if:

• They employ a relative and pay them more than their job is worth
• They make excessive contributions to their pension, leaving themselves with less income
• They have a business that makes substantial profits but don’t pay themselves a dividend
• They’ve given an interest in their business to a relative or new partner

If your application isn’t successful

If you’re not successful with your variation, you can ask for a mandatory reconsideration. And if this doesn’t work, you can appeal. The good thing about going through this process is that once you get to the appeal stage, your case will be decided by an independent panel rather than the CMS.

Tip: always keep a written record of your communications with the CMS. If you talk to someone on the phone, it’s a good idea to follow it up with a letter or email to put things in writing.

If you don’t agree with the CMS’s decision at any stage, you can make an appeal. Appeals are decided by an independent tribunal which can get much more detailed information from your child’s other parent and from the CMS.

You shouldn’t appeal just because there’s been a delay or you’ve received poor service – in these circumstances it’s better to complain. See our page on using the Child Maintenance Service for more on complaining.

Benefits to appealing

Having an independent tribunal involved can be useful for many reasons.

• The CMS will have to explain how it worked out your child’s other parent’s income and what evidence they used.
• You might see paperwork that includes details of your child’s other parent’s income.
• They can demand more in-depth information from your child’s other parent.
• They’ll check that the information given to the CMS is correct.
• If your child’s other parent has complicated finances, you can request that a finance professional sits on the tribunal. This is usually an accountant who can unpick all the finances in detail.

How to appeal

You’ll need to download form SSCS2 from gov.uk, fill it in and send it to the address on the form. You should appeal within 1 month of the date of your mandatory reconsideration notice. Include as much information as possible, including details of their decision and your reasons for appealing. 

The appeals process

When the CMS gets your appeal it will prepare a response and send you a copy. The paperwork is then sent to an independent tribunal. The tribunal will either make a decision based on what they see or hold a hearing that you can go to. 

It’s usually best to ask for a hearing, as this gives you a chance to explain your case and to answer any questions. The tribunal is not part of the CMS.

There can be 2 stages to the tribunal process. The first stage tribunal considers your appeal and makes a decision. Things usually end here. You can only appeal to the second stage of the process if the tribunal has made a legal mistake, such as misinterpreting the law.