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Challenging what the CMS says you should pay

This advice applies to Scotland

The Child Maintenance Service (CMS) will write to tell you how much maintenance you should pay. If you’re not sure how they worked that out, talk to an adviser.

You can ask the CMS to look again at their decision on how much you have to pay if:

  • you think their decision is wrong

  • your circumstances have changed - like if you have a child with your new partner

  • you have ‘special expenses’ - like the cost of travel to see your child, school fees or debts with your former partner

You’ll have to keep paying the amount the CMS told you to pay while they’re considering your request. 

If you think the CMS decision is wrong

You can ask the CMS to look at their decision again at any time if it’s wrong because they made an ‘official error’. This means they either:

  • made a mistake

  • based their decision on a mistake by the Department for Work and Pensions  (DWP) or HM Revenue and Customs (HMRC)

Asking for mandatory reconsideration 

If you think the decision is wrong, you can ask the CMS to look at their decision again. This is called asking for a ‘mandatory reconsideration’. You should say why you think the decision is wrong. 

You can call the CMS or write to them. It’s best to ask in writing so you have a copy of your letter or email. You’ll need the 12-digit reference number on the letter saying how much you have to pay. If you can’t find your reference number, you’ll need to give:

  • your name

  • your address

  • the name and date of birth of the child you’re paying maintenance for

The contact details are:

Child Maintenance Service

Child Maintenance Service 21

Mail Handling Site A

Wolverhampton

WV98 2BU

Telephone: 0800 171 2345

Relay UK - if you can't hear or speak on the phone, you can type what you want to say: 18001 then 0800 232 1975

You can use Relay UK with an app or a textphone. There’s no extra charge to use it. Find out how to use Relay UK on the Relay UK website.

Monday to Friday, 8am to 7.30pm

Saturday, 9am to 4.30pm

Calls are free from mobiles and landlines.

If you’re sending a letter, ask the Post Office for free proof of postage - you might need to show when you sent it. 

If you can show the calculation is wrong, you should send a copy of that too. For example, you might have payslips to show you earn less than the CMS said.

If you call, make a note of when you called, who you spoke to and what they told you. Follow your call up with a letter or email so you have a written record. 

Ask within 1 month of the decision

Check the date on your decision letter. You need to ask for a mandatory reconsideration within 1 month of the date on that letter. Explain why you disagree with the decision. 

If you’re close to the 1 month deadline, call the number at the top of your decision letter instead of writing.

If you miss the 1 month deadline

It's still worth asking for a mandatory reconsideration. 

You’ll need to explain why your request is late - for example, if you were ill or dealing with difficult personal circumstances. You don’t need to have proof of why it’s late, but if you do you should send it with the form. For example, if you were in hospital, coping with a bereavement or had an emergency at home.

You’ll also need to explain why you disagree with the decision. 

The CMS can refuse your application if it's late. You can still appeal to a tribunal if you apply within 13 months of the date on your decision letter.

Getting a decision - mandatory reconsideration notice

Once the CMS has made a decision, you’ll get a letter with the outcome. This letter is called a ‘mandatory reconsideration notice’. Keep it safe - you’ll need it if you want to appeal. You’ll get 2 copies of the notice so you can send one with your appeal. 

If the CMS changes their decision, they’ll change the amount you need to pay and backdate it to the date of their original decision. 

If they don’t change their decision, you’ll have to keep paying the amount the CMS originally told you to pay. 

Appealing a decision after a mandatory reconsideration

If you’re unhappy with the result of the mandatory reconsideration, you can appeal to an independent tribunal. It’s free and you don’t need a lawyer.

Coronavirus - if you’re appealing a child maintenance decision to the tribunal

If possible, a tribunal judge will assess your case without a hearing. Instead they’ll make a decision based only on the documents.

Send any evidence you have as soon as possible - for example, financial documents like bank statements.

If the judge assesses your case based on the documents, they’ll send you a ‘provisional decision’. If you don’t agree with the provisional decision, tell the tribunal you want a hearing instead.

If there has to be a hearing, the tribunal might suggest a phone call or video conference.

Tell the tribunal as soon as possible if you will find it difficult to have a remote hearing. For example, tell them if you don’t have the equipment for a conference call. You can find out what happens at a remote hearing on GOV.UK.


You must appeal within 1 month of the date of the mandatory reconsideration notice. If you miss that deadline, you might be able to ask for a late appeal. You must give as much detail as possible for why your late appeal should be allowed.

You can read more about making an appeal on GOV.UK. 

The time limit for a late appeal is 13 months from the date of the mandatory reconsideration notice. In exceptional circumstances, the tribunal might extend the 13-month time limit. For example, if you didn’t get a copy of the notice.

If you don’t want your former partner to know where you live

You can ask the tribunal to keep your address confidential. If you need to do this, tell the tribunal when you send in your appeal.

If your circumstances change

Coronavirus - if your circumstances have changed

At the moment, you might have to report a change of circumstances in a different way - even if the change isn’t because of coronavirus. 

You can find out how to report a change of circumstances on GOV.UK.

Every year the CMS will review how much you have to pay. When they do, they might say you have to pay a different amount. 

If your circumstances change between reviews, you can ask the CMS to look again at how much you have to pay. For example, if you have a new baby or you lose your job. The amount you pay will only be changed if your income changes by at least 25%. 

Check what changes you need to report

You could be fined up to £1,000 if you don’t report certain changes to the CMS.

You must tell the CMS within 7 days if you change:

  • your address

  • your job

You must tell the CMS within 14 days if your income goes up by 25% or more. You don’t have to do this if you're self-employed as the CMS will get the information it needs from your tax returns.

Example

Sam earns £300 a week before tax. This goes up to £350 a week. This is a change of just 16.5% so not enough to make a difference to the assessment. 

If Sam’s pay goes up to £375 a week, this is an increase of 25% and he must report it to the CMS. The CMS will reassess what he has to pay to take this into account. 

Coronavirus - if you’ve been furloughed 

You’ll be getting 80% of your salary. The CMS has said they can’t reduce your assessment because the change to your salary is less than 25%.

Call the CMS if the change is 25% or more - for example, if you’re on sick pay while you’re self-isolating or if you’ve lost your job. If you’re self-isolating, the CMS might reduce your payments for that period. They’ll send you a new payment schedule.

You should also tell the CMS about changes which affect how much maintenance you might have to pay - for example, if:

  • you move in with a new partner who has a child

  • your child no longer counts as a child, for example, because they’ve left approved education - check what’s approved education on GOV.UK

  • your arrangements for sharing care of the child change

  • the child dies

  • you become entitled to a benefit - like Universal Credit 

  • you go to prison

You don’t need to report a change until it's happened. If the change is likely to mean you pay less maintenance, you should report it as soon as you can. If the CMS changes how much you pay because of a change of circumstances, that change will usually take effect from the date you reported it. 

Check how to report changes

You can report changes through your online account or by calling the CMS. You can check what you can report by phone and online on GOV.UK.

You’ll need your 12-digit reference number when you call - you can find this on letters from the CMS. If you can’t find your reference number, you’ll need to give:

  • your name

  • your address

  • the name and date of birth of the child you’re paying maintenance for

Child Maintenance Service

Telephone: 0800 171 2345

Relay UK - if you can't hear or speak on the phone, you can type what you want to say: 18001 then 0800 232 1975

You can use Relay UK with an app or a textphone. There’s no extra charge to use it. Find out how to use Relay UK on the Relay UK website.

Monday to Friday, 8am to 7.30pm

Saturday, 9am to 4.30pm

Calls are free from mobiles and landlines.

Check when you’ll start paying the new amount

You’ll have to pay the new amount from either the date:

  • you reported the change – like when you told the CMS your shared care arrangements changed

  • the change happened – like when your income went down by 25%

If you disagree with the new amount, you’ll have to ask for a mandatory reconsideration.

If a change in circumstances means you’ve paid too much

If you have arrears, any overpayments could be used to help pay them off. 

If you don’t have any arrears, you’ll pay less until you’ve got the overpayments back. 

If you don’t have to pay maintenance anymore, the CMS can pay back any money you overpaid.

If you have ‘special expenses’ - asking for a variation

You can ask the CMS to change the amount you have to pay if you have ‘special expenses’. This is known as asking for a ‘variation’. Special expenses are:

  • the cost of keeping in touch with your children

  • the extra costs of looking after a sick or disabled child

  • previous debts you’re liable to pay which you ran up as a couple before you separated

  • boarding school fees

  • some mortgages, loans and insurance policies

You might be able to get a variation if you’re paying at least £10 a week for special expenses. You can claim in more than one of the categories. The £10 minimum applies to each category. There’s no minimum if the costs relate to a child with a long-term illness or a disability. 

If the CMS accepts your request, it can reduce what they count as your gross income by the amount of those expenses. Your gross income is your income before things like tax and national insurance have been deducted. 

Example 

Zac earns £450 per week and pays child maintenance for 2 children who live with their mother Jo. 

Zac has no other children and doesn’t share care with Jo. He pays maintenance at the basic rate for 2 children which is 16%. 

He’s been paying £72 a week (16% of £450 is £72).

Jo moves away with the children and it now costs Zac £35 per week to see them. He applies for a special expenses variation.

The variation is accepted and the £35 is deducted from his weekly income (£450 - £35 = £415). The amount he has to pay is then recalculated. His payments are reduced to £66.40 per week (16% of £415 is £66.40). 

This takes effect from the date of Zac applied for a variation.

If you have extra costs to keep in touch with your children

You can claim costs involved in keeping in touch with the children you’re paying maintenance for. These are also called ‘contact costs’.

Costs can include fuel, train or bus fares and overnight accommodation. They don’t include meals. 

If you have extra costs for looking after a sick or disabled child

You might be able to claim extra costs if your new family includes a child who’s sick or disabled. 

The child’s illness must be expected to last 52 weeks or more, unless the child is terminally ill. They’ll also count as disabled if they’re registered blind.

The child must be entitled to one of the following:

  • the care component of Disability Living Allowance (DLA)

  • the daily living element of Personal Independence Payment (PIP)

The mobility components of DLA and PIP don’t count. 

The CMS will deduct the amount of benefit from the costs before calculating the variation. 

Example

Amy pays £80 a week for a carer to help with her disabled son’s care. Amy gets DLA of £23.60 a week. This is deducted from the £80 she pays the carer (£80 - £23.60 = £56.40). 

The amount of special expenses the CMS will take into account is £56.40.

You can claim things like personal care, medical aids which aren’t available on the NHS, extra heating and changes you’ve had to make to your home. Personal care includes help with dressing, feeding, washing, advice and emotional support. Medical aids include walkers, wheelchairs and bathing aids.

If you have debts from your previous relationship

You can ask for a variation if you have to pay back certain debts that were run up before you and your partner separated. For example, a loan taken out for home improvements. These debts are also called ‘prior debts’. 

The loans must have been for the benefit of:

  • you and your former partner when you were a couple

  • the person looking after the child on a daily basis

  • any child you’re paying maintenance for

  • any child of yours or your former partner who lived with you before you separated

The loans must be from a registered lender. They can’t be:

  • business or gambling debts

  • credit card repayments

  • fines 

  • the legal costs of separation or divorce

  • a debt to buy something you’ve kept - like a loan for your car

  • a mortgage or loan secured on a property unless it’s where the child and the parent who’s caring for them live

  • debts you’re responsible for under a court order

If you pay boarding school fees

You might be able to claim expenses if you pay towards the boarding school fees for a child you’re paying maintenance for.

If you've got a mortgage, loan or insurance policy

You might be able to claim expenses if you pay a mortgage, loan or insurance policy on the home where the other parent and the children are living. 

You won’t be able to claim these costs if the loan was taken out in your name or if you have a legal share in the property.

Check when the CMS won’t agree to a variation

Even if the expenses you’re claiming are special expenses, the CMS won’t agree to a variation if:

  • you’ve been asked to pay the flat rate of £7 or the nil rate

  • your gross weekly income is £3,000 or more after deducting the special expenses

  • you’re getting income-based Jobseeker’s Allowance (JSA), Income Support (IS) or income-related Employment and Support Allowance (ESA) 

  • you’re getting Universal Credit and aren’t earning anything

  • you’re paying a default rate of child maintenance 

Even if none of these things apply, the CMS will only agree to a variation if they think it would be fair. They can look at the following things to decide if it’s fair:

  • the welfare of any child who might be affected - for example, if you can’t afford to travel to visit your child unless the amount you pay is reduced by a variation

  • if you could afford to meet the costs of special expenses by using money you currently spend on things which aren’t essential

Applying for a variation

You can ask for a variation before or after the CMS has calculated how much you should pay. It’s best to do this as soon as you know about the extra expenses. 

You can call the CMS or write to them. It’s best to ask in writing so you have a copy of your letter or email. You’ll need the 12-digit reference number on the letter saying how much you have to pay. If you can’t find your reference number, you’ll need to give:

  • your name

  • your address

  • the name and date of birth of the child you’re paying maintenance for

The contact details are:

Child Maintenance Service

Child Maintenance Service 21

Mail Handling Site A

Wolverhampton

WV98 2BU

Telephone: 0800 171 2345

Relay UK - if you can't hear or speak on the phone, you can type what you want to say: 18001 then 0800 232 1975

You can use Relay UK with an app or a textphone. There’s no extra charge to use it. Find out how to use Relay UK on the Relay UK website.

Monday to Friday, 8am to 7.30pm

Saturday, 9am to 4.30pm

Calls are free from mobiles and landlines.

If you’re sending a letter, ask the Post Office for free proof of postage - you might need to show when you sent it. 

If you call, make a note of when you called, who you spoke to and what they tell you. Follow your call up with a letter or email so you have a written record. 

You must say which of the special expenses you’re claiming and why.  

The CMS might ask you for more information. If they do, you should send it to them within 14 days. 

If the CMS accepts your application for a variation, they will tell the other parent. The other parent has 14 days to say if they disagree. They could also ask for a variation - check what they can ask for a variation for

If the other parent disagrees, you have 14 days to comment on anything they’ve said. 

Once the CMS has considered all the information, it might change what you have to pay.

Check when you’ll start paying the new amount

When you’ll have to start paying the new amount depends on the reason for the variation and when you applied for it. 

If the reason for the variation existed when you were told you had to pay maintenance

The CMS will backdate the new amount to the date they first said you had to pay child maintenance. 

The CMS can only do this if you tell them either:

  • before they make the calculation

  • within 30 days of being told of the amount of the calculation

If you apply later than that, the variation will start from the date you told the CMS you wanted to apply for a variation.

If the reason for the variation happened after you starting paying maintenance

You’ll have to pay the revised amount from the date you asked the CMS for a variation. For example, if it will cost you more to travel to see your children because they’ve moved house, the variation will start from the date you applied. It doesn’t matter when they actually moved. 

If you want to complain about the service you got from the CMS

If you’re not happy with the service you’ve received from the CMS rather than with a decision they made, you can make a complaint. Read more about complaining about the CMS

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