Financial remedy cases often settle through negotiation long before a consent order is sealed. But what happens when the parties reach “agreement in principle” yet still argue over the details? The Xydhias line of cases provides the answer—and the recent High Court decision in HA v EN [2025] EWHC 2436 (Fam) adds an important new layer.

The Background

In HA v EN, the husband and wife had reached terms that were accepted to amount to a Xydhias agreement. But all was not plain sailing. The wife’s legal costs and the mechanics of selling the family home (FMH) remained hotly contested. The FMH sale price also looked uncertain, raising the risk of a shortfall.

The court therefore had to decide:

• What exactly had the parties agreed?
• Could the court “fill in the gaps” on unresolved implementation issues?
• Was there scope to revisit the agreement if the FMH realised less than expected?

The Xydhias Principle

The leading case of Xydhias v Xydhias [1999] established that once parties have reached a clear agreement in financial remedy proceedings, neither can simply walk away before a consent order is drawn. However, unlike in pure contract law, the agreement is not automatically enforceable: the court must still approve it as fair under section 25 of the Matrimonial Causes Act 1973.

Subsequent cases (Rose v Rose, Kicinski v Pardi) have distinguished between:

• Xydhias agreements – binding in principle, but still subject to fairness and judicial approval.
• Rose orders – agreements actually approved by a judge at FDR or in court, which carry even greater weight.

What’s New in HA v EN?

Deputy High Court Judge Richard Todd KC confirmed the core Xydhias approach: where the broad terms are agreed, the court can resolve peripheral disputes (like costs or sale mechanics) without unravelling the deal.

But he went further. He noted that the Matrimonial Causes Act 1973, sections 34–35, provides a statutory mechanism to vary or rescind “maintenance agreements” in certain circumstances. While rarely used, Deputy High Court Judge Richard Todd KC suggested these provisions could, in principle, allow the court to revisit a Xydhias agreement if fairness so required—for example, if the FMH sold for far less than assumed when the deal was struck.

This opens the door to a nuanced safety valve: most Xydhias agreements will hold firm, but if events make the outcome manifestly unjust, limited variation may be possible.

Why It Matters

• Flexibility with certainty: HA v EN confirms that courts will give effect to Xydhias agreements, ironing out drafting and implementation issues rather than letting parties resile.
• The fairness filter: As ever, the court must still test the outcome against section 25 MCA 1973.
• Variation is possible: The judgment points to a rarely-discussed route (ss.34–35 MCA) to vary agreements if circumstances change dramatically.
• Contractual debate continues: Deputy High Court Judge Richard Todd KC also revisited Soulsbury v Soulsbury, which recognised a contract outside the MCA context, highlighting the blurred line between contractual enforceability and family law discretion.

Final Thought

HA v EN shows the Xydhias doctrine is still evolving. For practitioners, the message is twofold: record agreements clearly, but be aware that the court retains both the power and duty to ensure fairness—and, in rare cases, to adjust agreements if unforeseen events threaten to make them unjust.