Disputes about children are always emotionally charged. When those disputes become intertwined with child maintenance, positions can quickly harden — particularly where one parent seeks a 50:50 shared care arrangement and the other opposes it.
In many cases, arguments about equal shared care are not solely about parenting time. They are also about financial consequences.
This creates a dangerous dynamic:
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Children arrangements become battlegrounds for financial leverage
- Disputes over the exact number of overnight stays
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Financial remedy proceedings stall while child arrangements are litigated
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Children are exposed to prolonged uncertainty
However, The recent decision in OS v DT [2025] EWFC 156 (B), given by HHJ Hess and certified as citable, marks a significant development in child maintenance law where parents share the care of their children “exactly equally”. Although the case arose from a high-value financial remedies dispute, its wider importance lies in clarifying when the court, rather than the Child Maintenance Service (CMS), has jurisdiction to make child maintenance orders where there is an exactly equal shared care arrangement.
The Financial Reality Behind 50:50 Shared Care
Under the statutory child maintenance scheme, the amount payable depends significantly on:
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The paying parent’s gross income
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The number of children
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The number of nights the child spends with each parent
If care reaches a 50:50 arrangement, child maintenance may be reduced significantly — or in some cases, no maintenance is payable at all.
The result? Children arrangements become tactical.
The Jurisdictional Divide: CMS vs The Court
The Child Maintenance Service generally has jurisdiction to assess and collect child maintenance where:
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Both parents are habitually resident in the UK
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The paying parent’s income falls within the CMS calculation limits
However, there are important exceptions where the Court retains jurisdiction, including:
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Where the paying parent’s income exceeds the CMS maximum threshold – top up maintenance
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Applications under Schedule 1 of the Children Act 1989 ie lump sum
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Cases involving educational expenses or special needs
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Where CMS does not have jurisdiction (e.g. certain international elements)
In those cases, the Court can make child maintenance orders.
This is not merely procedural — it has strategic and substantive consequences.
The Shared-Care Jurisdictional Problem
Under the Child Support Act 1991, the court is generally barred from making child maintenance orders where the CMS has jurisdiction.
Sections 8(1) and 8(3) prevent the court from exercising its powers if the statutory scheme applies.
However, regulation 50 of the Child Support Maintenance Calculation Regulations 2012 creates a unique complication in cases of exactly equal shared care.
The CMS can only calculate maintenance where one parent provides less day-to-day care than the other. In a case of truly equal care:
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There is no “non-resident parent”
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There is no primary carer
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The CMS cannot make an assessment
For years, practitioners debated whether:
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The CMS technically retained jurisdiction but would assess maintenance at £0, or
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The CMS had no jurisdiction at all — leaving the court free to act
OS v DT finally answers that question.
What HHJ Hess Decided
HHJ Hess held that:
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In cases of exactly equal shared care, the CMS has no jurisdiction under regulation 50.
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Because the CMS cannot act, the statutory bar in sections 8(1) and 8(3) of the 1991 Act does not apply.
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The court therefore retains its residual power under section 23(1)(d) of the Matrimonial Causes Act 1973 to make a child periodical payments order.
Crucially, he also ruled:
A party does not need to apply to the CMS first.
The court itself can determine whether care is exactly equal and proceed accordingly.
This removes procedural uncertainty and prevents unnecessary delay.
The outcome in OS v DT Although jurisdiction was established, the court declined to order child maintenance on the facts. The parents shared care equally and both emerged from the proceedings with substantial capital (just over £3.44m each), as well as strong earning capacity. HHJ Hess concluded that periodical payments were not necessary or fair. Instead, the court made a targeted child-related order: the father was to meet 75% of the children’s school fees, reflecting his greater resources and earning capacity. The case therefore shows that even where regular maintenance is inappropriate, the court can still make bespoke financial provision for children once jurisdiction is established.
Why OS v DT Matters
1. It Creates a Third Category of Case
We now have:
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Ordinary CMS cases
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“Top-up” cases for high earners
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True equal shared care cases where the court alone has jurisdiction
This is a significant structural clarification in child maintenance law.
2. It Shifts the Litigation Battleground
Establishing exactly equal care now has major legal consequences.
If care is:
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49/51 → CMS jurisdiction applies
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50/50 → CMS has no jurisdiction; court powers revive
That distinction may encourage disputes about:
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Overnight calculations
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Day-to-day care patterns
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The practical reality of parenting time
The risk, as with previous jurisdictional tensions, is that care arrangements become litigated not purely for welfare reasons but also for strategic financial advantage.
What remains unresolved While OS v DT settles the question of who decides, it leaves open how courts should decide how much maintenance to order in shared-care cases.
- Traditionally, judges have used the CMS calculation as a starting point. Here, the CMS would do nothing at all. Future cases will need to develop clearer principles on: assessing need where care is equal, reflecting shared parenting in quantum, and achieving consistency between courts.
The Broader Context: Financial Remedy and Children Arrangements
As highlighted in Dickson v Rennie, children arrangements and financial provision are intrinsically entwined.
OS v DT reinforces this reality.
Where shared care is genuinely equal:
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Housing needs may differ
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Income needs may be recalibrated
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School fees and extracurricular costs require tailored solutions
Financial remedy cannot be entirely separated from childcare patterns.
