09th May 2023

Calculating Child Maintenance: James v Seymour

By James Pirrie

Calculating Child Maintenance: James v Seymour


A version of this article by FLiP Director James Pirrie was first published in LexisPSL Family on 26 April 2023 and can be found here. A link to a PDF of the article can also be found at the bottom of this page. 

Top-up child maintenance and application of the CMS formula (James v

James v Seymour gives us help on costs and on the transparency questions (anonymity) but the names are likely to be with us longer and more prominently for the link in the guidance as regards child support.  So I will look at the first two elements briefly before focusing on the third.


It is important as a matrimonial variation case confirming an award of costs is appropriate on the basis of:

  • A refusal to negotiate openly
  • A failure to explain the basis of a claim
  • A failure to comply with procedural directions
  • Making ludicrous claims because this stymies chances of settlement.

Mostyn J endorsed the first instance judge’s view that there was no need to draw a causal link to the wasted cost and regarded a 50% award as “merciful” but checked that there had been an assessment as to capacity to pay.


Mostyn J insists on open doors to the family court where possible.

  1. Section 12 of the Administration of Justice Act 1960 is not a blanket reporting ban and does not prevent parties or the children from being identified. Quoting (himself in) re PP (A child: Anonymisation) [2023] EWHC 330 Fam, he said that reporting of the following was permissible:
  • That the proceedings related to a minor’s maintenance
  • The name, address or photograph of the children
  • The name, address or photogragph of the parents
  • The text or summary of the orders made.
  1. The standard rubric on judgments requiring anonymity is wrong in the absence of there having been an order under s12(1)(e) AJA’60.

Setting the stage for James v Seymour as to child support.

The importance of the decision requires us to do the back-story, which has been bubbling along since 2003.  A grid of approaches might, courtesy of this latest decision be laid out in table form (see the attachment “tables” at the bottom of this blog), filling in (in almost luddite shorthand) the elements as they stood before this decision:

(See table 1)

Then came a run of cases, starting November 2022:

CMX v EJX [2022] EWFC 136, a substantial (£18m plus) matrimonial case, where Moor J had to consider what child periodical payments should be provided on top of the capital provision (which obviously encompassed the applicant’s spousal maintenance claims).

  • Moor J accepted  the “beauty” of the CB v KB decision but could not reconcile the approach to the very wide range of outcomes that would be generated by the different numbers of children (£12,600 per child where there are four and £63,804 where there is one).
  • [We think of this as a “child-count conundrum: there are the marked differences in the CMS formula, which is at odds with the culture in our courts.]
  • The outcome of the formula was, the judge observed also far in excess of the budget for the child.

The same month (and perhaps before the circulation of the Moor J decision as it is not referred to) Mostyn J dealt with a matrimonial case Collardeau-Fuchs v Fuchs [2022] EWFC 135 and sought to refine his earlier approach saying @120 that:

  • The decision in CB v KB was only giving guidance for gross annual incomes of up to £650k (not referring to the obiter comment as regards what to do with higher incomes);
  • This approach was only to be adopted where the child support claim was subsidiary (eg to the overarching spousal claim, where he suggested it would often be dealt with perfunctorily); but that
  • Where the claim is under schedule 1, “it will be the centrepiece in the litigation”: “the child maintenance budget is the principal litigation battleground.”
  • The same applies, he thought (@121), where even though not a schedule 1 case, the child provision is not subsidiary as on a variation application or where there is no spousal maintenance claim.

And this was the case that launched the HECSA, the Household Expenditure Child Support Award, as the tool to address this element, with its details at para 129 that child maintenance covers the direct expenses of the child but also (the HECSA), which is a broad brush assessment of:

  • The expenses that the applicant has that they can’t meet themselves,
  • Which avoids their being burdened by unnecessary financial anxiety,
  • but which must exclude the applicant’s personal expenses that have no reference to their role as carer of the child.
  • The standard of living provided should be not out of kilter with that of the respondent; and
  • It will bear some sort of relationship to a relevant pre-separation standard.

Then March 2023 saw X v Y re Z no 4, in which Cobb J picked up the HECSA-baton in a schedule 1 case where the father pleaded the millionaires defence to disclosure and confirmed an annual income of around £2.7m.  Cobb J:

  • Confirmed his understanding that CB v KB’s encouragement to use the uncapped formula was only for matrimonial and similar cases
  • Set to once side the relevance of the formula in this case; and
  • Used the terminology of the HECSA in his careful analysis of the correct provision.

James v Seymour on child support

And so we got to the 19th April 2023.  This decision, involved two parties, each remarried and thus (eventually) with a focus only on the provision for two children 12 and 10, for whom maintenance had been set at £10k p/a each in July 2014.  The mother appealed provision of £26,400 in total, seeking £91,700 in total.  Mostyn J dismissed the appeal but along the way provided further help on the principles, which we have sought to interpret, summarise and fit into our grid, showing where new guidance is being provided:

(See table 2)

The Child Support Starting Point (from the appendix)

(See table 3)

Where do we go from here?

One can reasonably anticipate significant uptake of this approach – as with so much of Mostyn J’s guidance it is compelling and provides a clear step by step approach.

It feels as though it is the start of a reconciliation that has stretched back over twenty years: the tension between the “use the formula” encouragement (of Mostyn J and others) and the “carry out the discretionary balancing exercise” that seems to emerge as the mandate from the bulk of other authorities.

It also surely cuts the increasingly stretched nexus between (1) matrimonial scale provision for children and (2) schedule 1 [and similar] provision.

With these two paths now diverging, one can reasonably anticipate:

A relatively fixed approach to the conventional (i.e non-complex case) adopting the CMS formula below the cap and the Mostyn table above it

The spawning of arguments and then criteria that justify the HECSA-based approach, likely to take in issues of:

  • Relativity to lifestyle during the relationship (“kilter 1”)
  • Relative lifestyle between the applicant and respondent (“kilter 2”)
  • What are applicant costs that do not reference the care of the child
  • Whether and how changes in the applicant’s circumstances (earning – cohabitation – remarriage – further children with a new partner) impact the award.

Whether the first order in effect fixes provision and what else should weigh in on the variation application beyond indexation. About time that we saw the airing of that other table from earlier editions of At A Glance, the National Foster Care Association’s guideline which showed the increasing costs of older children.

I am sure there will be niggles, for example why should a wealthy respondent contribute (relatively) minimally towards the needs of expensive children under schedule 1, just because the applicant is wealthy too.  Surely the right way is to look at the overall costs of such children and divide them equally if both can afford to pay.  However, the gateway to the HECSA as currently constituted by para 129b of Collardeau-Fuchs requires the applicant to be unable to cover those expenses from their own means.

There still seems to be a lot for Mostyn J’s judicial brothers and sisters to pin down for poor clients struggling with their schedule 1 case to have clearer guidance paving the way to settlement.

If you would like to speak to a family law specialist about child maintenance, please contact director James Pirrie (E: jp@flip.co.uk or T: 020 7420 5000) or contact any of our other specialist divorce lawyers:

T: +44 (0)20 7420 5000

E: hello@flip.co.uk