In family law, the term “final order” is sometimes misleading. The recent decision in Collardeau v Fuchs [2025] EWFC 307 shows how even a carefully crafted final financial remedy order can be revisited when enforcement problems and major breaches arise.

Background

This case is the latest in the long-running litigation between Alvina Collardeau and Michael Fuchs. Following the breakdown of their marriage, Mostyn J made a Final Order in June 2023, based heavily on the couple’s prenuptial agreement. W was granted continued occupation of the West London family home (“WLH”) until 2039, with H obliged to pay the mortgage and other household outgoings.

But H failed to comply. Mortgages went unpaid, properties were repossessed or sold off, and W faced mounting costs. In March 2025 she applied to enforce and vary the Final Order.

Enforcement – the limits of compliance

The Court heard evidence of repeated non-compliance by H. He failed to pay mortgage instalments, did not transfer properties as ordered, and even engaged in transactions designed to frustrate enforcement. Mr Justice Poole was blunt: H had been “prepared to see his children be compelled to leave their family home rather than comply with his obligations.”

Enforcement orders were therefore essential – requiring H to meet arrears, pay costs, and indemnify W in relation to certain liabilities .

Variation – section 31 MCA 1973 and the Thwaite jurisdiction

The more complex issue was whether the Final Order could be varied. Under s.31 of the Matrimonial Causes Act 1973, periodical payments orders (including those framed as undertakings) can be varied or capitalised into a lump sum. The Court applied the principles from Pearce v Pearce [2003], capitalising periodical payments using the Duxbury formula.

Separately, the Court considered the so-called Thwaite jurisdiction (Thwaite v Thwaite [1981] 2 FLR 280). Where an order is still executory (not yet fully implemented) and there has been a significant change in circumstances, the Court may vary it if it would be inequitable not to. Here, the loss of WLH through repossession and H’s persistent default amounted to just such a change .

What was ordered?

• H’s undertaking to pay the mortgage until 2039 was discharged and replaced with a capitalised lump sum of £11m, reflecting what he should have paid.
• Other claimed costs (such as legal fees and property expenses) were not included, as they went beyond the scope of the Final Order.
• Periodical payments linked to staff and household costs were replaced with quantified orders, making enforcement simpler.

Practical lessons

1. Final doesn’t always mean final – Where an order remains executory, the Court can revisit it under Thwaite if compliance breaks down.
2. Evidence is key – W succeeded in part, but failed on some claims because she could not prove the sums were properly incurred. Even in high-value cases, documentary evidence matters.
3. Capitalisation as protection – Courts may prefer a lump sum to uncertain periodical payments where a payer repeatedly defaults.
4. Procedure is flexible – Although W’s application was technically issued under the wrong procedure, the Court cured the defect to avoid injustice.

Conclusion

Collardeau v Fuchs is a striking reminder that family law orders are living instruments. They can be enforced with teeth, but also adapted when circumstances fundamentally change. For practitioners, it reinforces the importance of distinguishing between true finality and executory obligations – and of ensuring applications are backed by clear, persuasive evidence.