Fri 10 Jul 2026

When “Sign This or the Marriage Is Over” – Can a Post-Nuptial Agreement Be Challenged?

Post-nuptial agreements can provide certainty, protect family wealth and help couples avoid costly disputes in the future. But what happens when one party later claims they signed the agreement under pressure? A recent Scottish decision, L v I [2026] SC STI 84, offers a potted insight into how the courts approach exactly that question.

This wasn't a case where the court decided the post-nuptial agreement was unfair. The court was asked whether the spouse challenging the agreement had pled enough to justify a full hearing of evidence. The answer was yes, but the decision captures the legal approach quite nicely.

A situation family lawyers see all too often

Relationships are rarely black and white.

Many agreements are negotiated at times when one party is feeling vulnerable, anxious about the future or worried about the consequences of refusing to sign. Sometimes there is a significant imbalance in wealth. Sometimes one spouse is simply in a stronger position than the other.

In L v I, the pursuer alleged that she was effectively presented with an ultimatum: sign the agreement or the marriage was over. She also claimed that the agreement provided no meaningful benefit to her and produced a significantly unequal financial outcome in favour of her spouse.

Whether those allegations are ultimately proved remains to be seen. However, the sheriff concluded that these were precisely the type of circumstances that could be relevant when assessing whether an agreement was fair and reasonable.

No surprises in the law – but an important reminder

This judgment gives recognition to the leading authorities.

The court reaffirmed the long-established principle from Gillon v Gillon that the key question is whether the agreement was fair and reasonable at the time it was entered into. That assessment requires the court to look at the whole picture, including matters such as pressure, vulnerability, bargaining position and legal advice.

The sheriff also relied upon Bradley v Bradley, confirming that a party challenging a nuptial agreement must explain what makes the agreement unfair and what practical consequences flow from it.

Consistent with Bryce v Bryce, the court recognised that a very significant financial imbalance can be an indicator of unfairness, particularly where one party receives little or no corresponding benefit.

In short, this decision does not create new law. Instead, it demonstrates the continued willingness of Scottish courts to scrutinise the real circumstances surrounding the signing of a nuptial agreement rather than simply focusing on the fact that a document was signed.

So, how can you challenge a nuptial agreement?

One of the questions we are most often asked is: "Can I actually challenge a pre-nuptial or post-nuptial agreement?"

The answer is yes, but not simply because you have changed your mind or because the agreement now appears to be a poor bargain.

Under section 16 of the Family Law (Scotland) Act 1985, the court can set aside or vary a nuptial agreement if it was not fair and reasonable at the time it was entered into. As L v I demonstrates, the focus is on the circumstances that existed when the agreement was signed, rather than whether the outcome seems unfair years later.

Some of the factors that may be relevant include:

  • Pressure or coercion to sign the agreement
  • A significant imbalance in bargaining power between the parties
  • One party being emotionally vulnerable at the time of signing
  • A lack of meaningful benefit to one spouse coupled with a markedly unequal financial outcome
  • Concerns about the quality, timing or practical effect of legal advice received before signing
  • Any wider circumstances that may call into question whether the agreement was genuinely fair and reasonable when it was entered into

L v I reminds us that courts are prepared to look beyond the existence of a signed agreement and examine the reality of what was happening in the relationship at the time. The pursuer's allegations that she was told the marriage would end if she did not sign, together with claims of distress and a markedly unequal financial outcome, were enough to justify a full evidential hearing.

That does not mean every challenge will succeed. Far from it. Many nuptial agreements are upheld. However, where there are genuine questions about fairness, pressure or imbalance, specialist legal advice can be invaluable in assessing whether there are grounds to challenge the agreement.

What about legal advice?

One of the most notable aspects of the case is that the pursuer had received legal advice before signing.
Many people assume that once independent legal advice has been obtained, the agreement becomes virtually untouchable. That has never been the law in Scotland, and this judgment is a useful reminder of that fact.

The sheriff accepted that legal advice is undoubtedly an important factor. However, it is only one factor. The court may still consider the wider circumstances in which the agreement was negotiated and signed.

That is why careful drafting, full financial disclosure and a well-managed negotiation process remain so important.

Conclusion

  • The court looks at whether the agreement was fair and reasonable when it was signed
  • The surrounding circumstances matter just as much as the wording of the document
  • Allegations of pressure, vulnerability or unequal bargaining power can be relevant
  • Independent legal advice is highly important but not necessarily decisive
  • A significant imbalance in outcome may invite closer scrutiny by the court
  • Courts will often require a hearing of evidence before deciding whether an agreement should stand or fall

The bigger picture

For family lawyers, L v I is a reminder of something we see regularly in practice: relationships are emotional, complicated and rarely fit neatly into legal boxes.

The best nuptial agreements are not simply technically correct. They are negotiated carefully, transparently and in circumstances where both parties feel informed, properly advised and comfortable with the outcome. Taking those steps at the outset can significantly reduce the risk of disputes later on.

Equally, if you have already signed an agreement and are now questioning whether it was truly fair and reasonable, it is important to seek advice sooner rather than later. Every case turns on its own facts, and an experienced family lawyer can help assess whether there may be grounds for a challenge.

At MFMac, our family law team regularly advises clients on the preparation, negotiation, enforcement and challenge of pre-nuptial and post-nuptial agreements. We understand that no two relationships are the same and that behind every agreement is a personal story and a family looking for certainty.

If you would like to discuss a nuptial agreement, or if you are separating and have concerns about an agreement you previously signed, please get in touch with one of our family law specialists. We'd be delighted to have a confidential conversation about your options and help you plan the best way forward.

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