In L v L [2021] EWFC B83 His Honour Judge Booth (sitting as a judge of the High Court) stated at [26] he had been referred to the concept of ‘matrimonialisation’ but it was ‘a word that I hope will not acquire common usage’.

Although not a word in the Oxford English Dictionary, His Honour Judge Booth’s hope has not come to fruition. In Standish v Standish [2024] EWCA 567 Richard Todd KC (for the appellant wife) invited the court (at [71]) to ‘remove [the category of matrimonialised assets] from the lexicon of the law on financial remedies’ and Timothy Bishop KC (for the respondent husband) suggested (at [93]) ‘the court might consider whether this concept merits being maintained at all’. However Moylan LJ (in a judgment with whom King and Phillips LJJs both agreed) stated at [161] the answer to ‘the question raised by both parties, namely whether the whole concept of matrimonialisation should no longer be applied’, was ‘it should continue to be applied’.

The principle that underpins matrimonialisation (at set out by Moylan LJ at [160]) is that ‘fairness may require or justify treating property, which was not purely the product of the parties’ joint endeavours, as matrimonial property and, therefore, within the scope of the sharing principle’ (original emphasis). It is ‘about when an asset or assets which were at one stage non-marital property might be included within the sharing principle’.

In JL v SL (No. 2) (Appeal: Non-Matrimonial Property) [2015] 2 FLR 1202 Mostyn J phrased the concept at [28] as a consideration of the treatment of non-matrimonial property which had become ‘part of the economic life of [the] marriage … utilised, converted, sustained and enjoyed during the contribution period’ (citing Guest J in the Australian case of Farmer and Bramley [2000] FamCA 1615 at [190]).

At [162] Moylan LJ makes it clear that ‘it would be wrong to state that, as a matter of principle, property which has a non-marital source can never be subject to the sharing principle’.

However, the principle has clearly been ‘checked’ by Standish. This is because ‘it is a derogation from the principle that sharing applies to matrimonial property and does not apply to non-matrimonial property’. As such:

‘it should be applied narrowly. This is so that it is not used by parties in a way which would undermine the clarity of the sharing principle, namely that it is the sharing of property generated by the parties’ endeavours during the marriage.’

Moylan LJ therefore stated at [163] that ‘it would be helpful to make clear, expressly, that the concept of matrimonialisation should be applied narrowly’. This is however ‘not a hard and fast line but remains a question of fairness’. He therefore proposed a slight reformulation of the guidance given in K v L (Non-Matrimonial Property: Special Contribution) [2011] 2 FLR 980 where Wilson LJ (as he then was) – and with whom Laws and Jacob LJJ agreed – had specifically addressed matrimonialisation. In K v L the husband relied on what Lady Hale had said in Miller/McFarlane [2006] 1 FLR 1186 at [148] that ‘the importance of the source of the assets will diminish over time’ (emphasis added). Wilson LJ stated (emphasis in original):

‘[18] Thus, with respect to Lady Hale, I believe that the true proposition is that the importance of the source of the assets may diminish over time. Three situations come to mind:

(a) Over time matrimonial property of such value has been acquired as to diminish the significance of the initial contribution by one spouse of non-matrimonial property.

(b) Over time the non-matrimonial property initially contributed has been mixed with matrimonial property in circumstances in which the contributor may be said to have accepted that it should be treated as matrimonial property or in which, at any rate, the task of identifying its current value is too difficult.

(c) The contributor of non-matrimonial property has chosen to invest it in the purchase of a matrimonial home which, although vested in his or her sole name, has – as in most cases one would expect – come over time to be treated by the parties as a central item of matrimonial property.’

Moylan LJ proposed a reformulation ‘having regard to the developments that have taken place since that decision’ namely:

‘(a) The percentage of the parties’ assets (or of an asset), which were or which might be said to comprise or reflect the product of non-marital endeavour, is not sufficiently significant to justify an evidential investigation and/or an[ything] other than equal division of the wealth;

(b) The extent to which and the manner in which non-matrimonial property has been mixed with matrimonial property mean that, in fairness, it should be included within the sharing principle; and

(c) Non-marital property has been used in the purchase of the former matrimonial home, an asset which typically stands in a category of its own.’

Moylan LJ stated at [164] that in (a) ‘the sharing principle would apply in conventional form’, in (c), ‘the court will typically conclude that the former matrimonial home should be shared equally although this is not inevitable as shown by cases such as FB v PS’.

At [165] Moylan LJ said that (b) required ‘a more nuanced approach similar to that referred to in Hart at [96], when the evidence does not establish a clear dividing line between matrimonial and non-matrimonial property’. He referred to JL v SL (No 1) (Appeal: Non-Matrimonial Property) [2015] 2 FLR 1193 per Mostyn J where at [18] he had said the underlying question is whether the asset or assets ‘should have the same character as those assets built up by their joint endeavours during the marriage, with the consequence that they should be shared … on divorce’ and he framed the question as ‘[d]oes fairness require or justify the asset being included within the sharing principle?’

Further at [166] it was said that the ‘conclusion that it does, however, does not mean that it must be shared equally’. Any suggestion that once an asset is matrimonialised and treated as matrimonial property ‘it must be shared equally is unsupported by any authority and would be contrary to the objective of a fair outcome’ (emphasis added). The reasons for this, as Mostyn J said in JL v SL (No 1) at [19], is it may be that the ‘non-matrimonial source of the moneys in question’ remains ‘a relevant consideration’.

Therefore Moylan LJ concluded that in its evaluation of all the relevant factors in the situation described in (b) above ‘it would be perverse if the court could not decide that the non-matrimonial source, in whole or in part, of an asset treated as matrimonial property could not justify an[ything] other than equal division’. Or to put it another way, and (as Moylan LJ acknowledged) repeating what he had said in Hart v Hart [2018] 1 FLR 1283 at [86]:

‘The court will have to decide, adopting Wilson LJ’s formulation of the broad approach in Jones, what award of such lesser percentage than 50% makes fair allowance for the parties’ wealth in part comprising or reflecting the product of non-marital endeavour.’

In WL v HL [2017] EWHC 147 (Fam) – the unreported decision later cited in WM v HM (Financial Remedies: Sharing Principle: Special Contribution) [2018] 1 FLR 313 at [11] – Mostyn J stated:

‘[38] I am firmly of the view that the correct approach to give effect to the sharing principle is to try to calculate the scale of the matrimonial property and then normally to share that equally leaving the non-matrimonial property untouched. This is logically pure, morally sound, easy to understand, and limits individual judicial caprice. I recognise that not everyone agrees with this approach …

[39] The (equal) sharing (of matrimonial property) principle is not a Procrustean bed. Cases have shown how it has been modified (some might say manipulated) to achieve an overall intuitively fair result. Thus it has been described as a tool and not a rule …’

In his speech Family law – not the poor relation delivered to the 19th Australian National Family Law Conference on 16 August 2022 Mostyn J said extra-judicially as follows:

‘[46] This is why I have always endeavoured to arrive at a figure for divisible matrimonial property which will be shared equally. True, the process of arriving at that figure for divisible matrimonial property may, sometimes, appear to be contrived. This takes us to Procrustes and his bed.’

After citing the above from WM v HM he continued:

‘[47] My disavowal of the practices of Procrustes was not perhaps very sincere. The truth is that those us who have wholeheartedly embraced the yardstick of equality do sometimes shrink the matrimonial property so that half of it gives what we feel is the right result. Shrink factors are pre-marital value and post separation endeavour.’

It could perhaps be argued that the concept of matrimonialisation is a reversal of this – increasing the matrimonial property so that half of it gives what judges feel is the right result. If so, and whether or not this could fairly be described as a Procrustean bed – forcing something to fit to an arbitrary standard – it is clear that matrimonialisation remains alive and well.