Nayyars Solicitors · Family Law Guide

Is a Prenup Legally Binding in the UK?

If you are planning a wedding and thinking about a prenuptial agreement, the first question is usually a simple one: will it actually hold up if things go wrong? It is a sensible question to ask, and the honest answer is more reassuring than many people expect.

In England and Wales, a prenup is not automatically legally binding in the way an ordinary contract is. However, the courts will usually follow a prenup that has been properly prepared and is fair, so a well-drafted agreement carries real weight. The law may also be about to change, with the government consulting in 2026 on making some agreements fully binding.

This guide explains where prenups stand today, what makes a court likely to uphold one, when it might not, and what the proposed reforms could mean for couples. Our family law team drafts and reviews these agreements regularly, so we have written it with the questions our clients ask most in mind.

Are prenups legally binding in the UK?

A prenuptial agreement (often called a prenup) is a written agreement made before marriage or civil partnership that sets out how money, property and other assets should be divided if the relationship ends. Couples often use one to protect a business, an inheritance, family wealth or property owned before the marriage.

In England and Wales, the final decision on how assets are divided on divorce rests with the court. Under the Matrimonial Causes Act 1973, a judge has a duty to reach a fair outcome, and a couple cannot simply sign that power away. That is why a prenup is not strictly binding.

In practice, though, the court treats a properly made prenup as a very important factor, and often the deciding one. The question a judge asks is not "is this a valid contract?" but "is it fair to hold this couple to what they agreed?"

Why courts usually follow prenups

The turning point came in 2010, when the Supreme Court decided Radmacher v Granatino. Katrin Radmacher, a German heiress, and her French husband had signed a prenup before their marriage. When they divorced, the Supreme Court held them to it, and the husband received far less than he would have done without the agreement.

The court set out a principle that still guides judges today: a court should give effect to a nuptial agreement that each person entered into freely, with a full appreciation of its implications, unless in the circumstances it would not be fair to hold them to it.

This is why prenups have become far more common in England and Wales, and not only among wealthy couples. They are now used by people marrying later in life, people with children from a previous relationship, and business owners who want certainty.

What makes a prenup more likely to be upheld

Because a judge will look closely at how the agreement was made, the process matters just as much as the wording. Family lawyers follow a set of well-established safeguards, many of them recommended by the Law Commission:

1. Each person takes independent legal advice from their own solicitor.
2. Both people give full and frank financial disclosure, setting out their income, assets, debts and pensions.
3. The agreement is signed at least 28 days before the wedding or civil partnership.
4. Neither person is put under pressure to sign.
5. The terms meet both people's reasonable needs and the needs of any children.

It also helps to include a review clause, so the agreement is revisited after major life events such as the birth of a child or a significant change in finances. A prenup that is ten years old and has never been updated is easier to challenge than one that has kept pace with the couple's life. Our prenuptial agreement solicitors build these protections in from the start.

When a court might not follow a prenup

A court may reduce the weight it gives a prenup, or set it aside altogether, where it would be unfair to hold someone to it. The most common reason is need. If following the agreement would leave one person unable to house themselves or meet basic living costs, especially where they have been caring for children, a judge is likely to step in.

The circumstances in which the agreement was signed also matter. A prenup produced the week before the wedding, signed without legal advice, or based on hidden assets is on much weaker ground. The same applies if one person was under real pressure, for example because guests had been invited and one partner threatened to call the wedding off.

Arrangements for children are always decided by what is best for them, so a prenup cannot limit child maintenance or settle where children will live. Where a prenup is challenged during a divorce, our financial settlement lawyers can advise on how much weight a court is likely to give it.

Already married? Postnuptial agreements

If you are already married or in a civil partnership, you can still make an agreement. A postnuptial agreement (or postnup) works in the same way as a prenup and is treated in the same way by the courts, so the same safeguards apply.

Postnups are often used when one partner receives an inheritance, starts a business, or when a couple want to record an agreement after a period of difficulty in the marriage. They can also be used to update a prenup that no longer reflects the couple's circumstances. For couples with significant or complex assets, our high net worth team can advise on structuring either kind of agreement.

It is also worth remembering that, under the current law in England and Wales, getting married automatically cancels any existing Will unless it was made in anticipation of that marriage. Many couples review their Wills at the same time as signing a prenup so both documents work together.

Scotland and Northern Ireland

The position is different across the UK. In Scotland, prenups are generally treated as enforceable contracts, and a court will only set one aside if it was not fair and reasonable at the time it was signed. Northern Ireland broadly follows the English approach, with courts giving significant weight to fair, properly made agreements.

If you or your partner have links to another country, or you signed a marriage contract abroad, the rules can become more complicated. Our international family law solicitors can explain how a foreign agreement is likely to be treated here.

Could prenups become fully binding?

Possibly, and soon. In June 2026 the Ministry of Justice launched a consultation called A Fairer End to Relationships, which closed on 14 August 2026. Among its proposals is the introduction of "qualifying nuptial agreements", which would allow couples to make binding financial arrangements in advance of divorce or dissolution.

The idea builds on recommendations the Law Commission made in 2014. Under that model, an agreement meeting set conditions, such as legal advice, disclosure and timing, would be binding except where it failed to meet either person's financial needs. Until any new law is passed, though, the Radmacher approach still applies, so it is important to make your agreement as robust as possible under the current rules.

Frequently asked questions

Conclusion

A prenup is not automatically legally binding in the UK, but in England and Wales a fair, properly prepared agreement will usually be followed by the court. The strength of your prenup depends on how it is made: independent legal advice, full disclosure, plenty of time before the wedding and terms that meet both people's needs.

With reform on the horizon, prenups may soon carry even more weight. For now, the best protection is an agreement drafted carefully under the current rules and reviewed as your life changes.

This article is for general information only and does not constitute legal advice. Every case depends on its own facts, so please contact Nayyars Solicitors for advice specific to your situation.