Last updated: August 2026
by Jess Knauf, Director of Client Strategy. Fact-checked by Belinda Atkins, Managing Director, Family Legal Ltd. Information reflects current family law and mediation requirements in England and Wales as of 6th August 2026.
Key Takeaways
- A south London electrician was assessed on his best trading year in a decade, months after the contract behind it had ended.
- The Child Maintenance Service uses the taxable profit on your last Self Assessment return, so a drop in income often takes a full tax year to show up.
- In two evening mediation sessions the parents built a base monthly figure, a share of profit above an agreed level, and a yearly review tied to the tax return.
- Named extras such as breakfast club and football subs were split separately, which a standard calculation does not cover.
- Start to finish took five weeks and cost far less than a contested application, and the arrangement survived the next quiet quarter.
SELF-EMPLOYED CHILD MAINTENANCE CASE STUDY
This self-employed child maintenance case study follows a London father whose Child Maintenance Service figure was based on a boom year, and who agreed a workable alternative with his ex-partner in two mediation sessions. They replaced one fixed number with a base payment, a percentage share of stronger years and an annual review date. Parents are free to agree their own arrangement at any point, and mediation is where most of these conversations land.
Most of what you read about paying maintenance on a variable income stops at the formula, which is why we wanted to publish a proper self-employed child maintenance case study instead. Numbers on a government calculator are one thing. A father in Croydon staring at a demand built on a year he can no longer repeat, while the children’s mother in Streatham needs to know what is landing in her account on the 1st, is quite another.
Money and children together make this one of the harder family disputes in London to settle over text message. The details below are a composite of cases we see, with names, jobs and figures changed. The shape of it, though, will be familiar to any freelancer, contractor or trade in the capital.
How Did This Self-Employed Child Maintenance Case Study Begin?
Dan is a self-employed electrician working across south London, mainly commercial fit-outs. He and Priya separated after eleven years and are divorcing. Their two children, aged nine and six, live mainly with Priya in Streatham and stay with Dan in Croydon two nights a week, which works out at just over 100 nights a year.
The trouble started with timing. Dan had one exceptional year, a long hotel refurbishment that pushed his taxable profit to around £58,000. That was the return HMRC held when Priya applied to the Child Maintenance Service. Run through the standard rates for two children, with the shared care reduction applied, the assessment came out at roughly £510 a month.
By the time that letter arrived, the refurbishment had finished and Dan was back on domestic jobs at maybe half the profit. He was not hiding anything. He simply could not evidence the drop until a newer return had been filed, and the CMS generally will not revisit a self-employed figure outside the annual review without one. We explain that mechanism in full in our guide to how the CMS assesses self-employed income.
Priya’s position was equally reasonable. She works in early years education, her rent had gone up again, and she had watched Dan turn up in a new van. From where she stood, a man who had earned £58,000 was pleading poverty. Neither of them was being unfair. They were looking at two different years.
Can Mediation Fix a Figure That Does Not Fit Real Income?
It can, because parents are allowed to agree whatever they both think is fair. The statutory formula is a fallback, not a ceiling or a floor. Dan called us after his accountant suggested it, and both parents attended a MIAM, the first individual meeting where a mediator explains the options in private. If you have not been to one, our walkthrough of what happens at a MIAM in London covers the format.
They chose two joint sessions online, at 7.30pm, because Dan is on site from seven and Priya has the children. Before the first session both sent in the same documents: three years of tax calculations and tax year overviews, business accounts, recent bookkeeping exports and a note of work booked in. The free financial disclosure checklist generator lists the same ground, and there is more on preparation in our post on getting ready for a first mediation session.
Session one: three years on one screen
The mediator put Dan’s profit for three consecutive years side by side: roughly £34,000, then £58,000, then £31,000. Seeing the shape of it changed the conversation within twenty minutes. Priya was not looking at a man who had earned £58,000 a year, she was looking at a man who had earned it once. Dan, for his part, accepted that in the good year he had drawn far more than he had ever offered to pay. Nobody had to be wrong for the numbers to move.
That is the practical value of financial disclosure in a room where nobody is scoring points. We use the same approach in wider money cases, which we set out in our page on financial mediation for London families.
“We see this pattern constantly with London trades and contractors. The argument looks like it is about money, and it is really about uncertainty. Once both parents can see three years of accounts at the same time, the negotiation stops being a fight about honesty and starts being a piece of planning. The agreements built that way tend to survive the next quiet quarter, because both people helped design them.”
Jess Knauf, Director of Client Strategy
Assessed on a year you can no longer repeat?
Start with a MIAM, where a mediator talks through your options privately. It is free if you qualify for legal aid, and many cases involving child arrangements also attract the £500 family mediation voucher.
What Did They Actually Agree?
Session two was about design rather than argument. Priya’s non negotiable was predictability, because she budgets to the pound. Dan’s was survivability in a thin month. Those two things are not in conflict once you stop insisting on a single flat number.
- A base figure: £380 a month by standing order on the 1st, set at a level Dan could meet in a poor year
- A share of the good years: 15% of taxable profit above £40,000, paid each February once his accountant has filed
- Named extras: breakfast club, football subs, school shoes and trips, split equally and agreed before either parent commits to them
- A review date: the week after the tax return goes in, so neither has to raise it awkwardly
- A cash flow allowance: recognition of the January and July payments on account, which is when self-employed money gets tight
| The CMS assessment | What they agreed in mediation | |
|---|---|---|
| Income used | One tax year, the strongest of three | Three years, averaged, plus a live share of profit |
| Monthly amount | About £510, fixed until the next return | £380 base, topped up annually in February |
| Extras | Not covered | Listed and split 50/50 by agreement |
| If income changes | Wait for a newer return to be filed | Built in review, every year, same date |
Figures are illustrative. The statutory rates behind the assessment are set out in the GOV.UK guide to how child maintenance is worked out (as of July 2026), and there is neutral, non commercial background on the whole system at childmaintenance.org.uk.
Could you get legal aid or the £500 voucher?
London Mediation Service is a Legal Aid Agency contracted provider for family mediation, so legal aid mediation is available through our service where you qualify (it is means-tested, and self-employed income is assessed on your accounts). Your MIAM is free if you qualify for legal aid. Many cases involving child arrangements also qualify for the £500 family mediation voucher, which is not means-tested. You can check your legal aid eligibility in a couple of minutes.
Does an Agreement Like This Hold Up?
Dan and Priya’s decisions were written up in a memorandum of understanding, a plain English summary of what they had settled. That is not a court order by itself, and either parent can still apply to the CMS later, which is exactly why an arrangement both people helped build tends to last longer than one imposed on them.
Because they were also divorcing, the maintenance figure was recorded alongside their wider financial settlement. One detail worth holding on to: under the Child Support Act 1991, a child maintenance clause in a court order only keeps the CMS out for 12 months from the date of the order. Our guide to whether a mediation agreement is legally binding explains how the memorandum and the order fit together.
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What Can Other Parents Take From This Self-Employed Child Maintenance Case Study?
Five weeks passed between Dan’s first phone call and the signed memorandum: two MIAMs, two joint sessions and a short third to check the wording. Compare that with a contested route through a London family court, where listing delays alone can run into months, and the case for trying a conversation first makes itself.
- Bring three years, not one: a single return tells the other parent almost nothing about a variable business
- Separate the base from the bonus: a survivable monthly figure plus a share of the good years suits trades and freelancers far better than a flat number
- Diarise the review: tying it to the tax return removes the need for anyone to start a difficult conversation
- Write down the extras: most later rows are about kit, trips and clubs, not the maintenance itself
- Do it before resentment sets in: it is much easier to design an arrangement than to unpick a year of missed payments
If your circumstances are shifting for other reasons too, it is worth reading our update on the changes to child maintenance rules affecting London parents. Session formats, evening slots and fees are all on our mediation services and prices page, and we work from Waterloo, St Pancras and Sutton as well as online.
If you would value some peer support alongside mediation, The Divorce Circle’s free parenting plan tool is a gentle place to start.
Summary
This self-employed child maintenance case study followed a south London electrician assessed on his strongest trading year, months after the work behind it had ended, and a mother in Streatham who needed a figure she could budget around. Neither was being unreasonable. In two evening mediation sessions they replaced a single fixed number with a base monthly payment, a 15% share of profit above an agreed level paid once the accountant files, an equal split of named extras, and a review pegged to the tax return. It took five weeks, cost far less than a contested application, and gave both parents something the formula could not: an arrangement that bends with the business instead of breaking against it.
Frequently Asked Questions
Can separated parents agree their own child maintenance instead of using the CMS?
Yes. Parents are free to agree any figure and any structure between themselves, and a family based arrangement carries no CMS fees. Either parent can still apply to the Child Maintenance Service later, so an agreement works best where both feel it is genuinely fair.
Why did the CMS use a year the father was no longer earning?
For a self-employed parent the CMS uses the gross taxable profit on the most recent Self Assessment return, supplied by HMRC. Outside the annual review it normally needs evidence of a newer return already filed before it will use a different figure, which can mean waiting for the tax year to close.
How many mediation sessions does a case like this usually take?
A MIAM each, then two joint sessions, is typical where both parents bring their documents and the dispute is about the figure rather than the relationship. In this case the whole process took five weeks, including a short final session to check the wording of the memorandum.
Is a base payment plus a share of profit a common arrangement?
It is one of the most useful structures for freelance, contractor and trade income. A minimum monthly amount protects the receiving parent’s budget in a quiet period, while a percentage of profit above an agreed threshold means stronger years are shared without the paying parent being locked into an unaffordable fixed figure.
What should a self-employed parent bring to the first session?
The last two or three years of tax calculations and tax year overviews, business accounts, recent bookkeeping or management figures, dividend and director’s loan details if you trade through a company, and an honest note of work booked in for the next six months. A short projection from your accountant helps.
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Ready to Take the Next Step?
London Mediation Service helps self-employed parents agree child maintenance that reflects how their income actually behaves, with FMC-accredited mediators in Waterloo, St Pancras and Sutton, or online around your working day. We are a Legal Aid Agency contracted provider for family mediation.
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London Mediation Service, as part of Mediate UK, works with trusted legal partners including DFA Law LLP and independent barristers, who support clients with consent orders, legal documentation and advice, and independent barrister reviews.