Prenuptial Agreement Challenges: When Are Prenups Most Likely to Fail?

Article summary

Prenuptial agreements are not legally binding contracts in English law, but a properly drafted agreement carries considerable weight in financial remedy proceedings following divorce, provided certain conditions are met.
An agreement will carry less weight if either party lacked independent legal advice, there was no full financial disclosure, or the agreement was signed so close to the wedding that genuine negotiation was impossible.
Needs take precedence over the terms of a prenuptial agreement where giving effect to those terms would leave a spouse without adequate financial provision. The court’s duty to children of the family cannot be contracted away.
A significant change in circumstances, particularly the arrival of children or a sharp change in one party’s financial position, can reduce the weight the court gives to an agreement made years earlier.
Courts have consistently respected prenuptial agreements that ring-fence inherited or pre-marital wealth, where both parties entered the agreement freely, with proper advice, and a clear understanding of what they were signing.

The Supreme Court’s decision in Radmacher v Granatino [2010] UKSC 42 transformed how prenuptial agreements are treated in England and Wales. The court held that a prenuptial agreement should be given decisive weight unless it would be unfair to hold the parties to it. That is still the governing test. What it means in practice depends, as always, on the specific facts.

The agreement is not a binding contract, and the court retains jurisdiction to depart from it. The question at a financial remedy hearing is whether departing from the agreement would be fair in the circumstances that exist at the time of the divorce. An agreement that was entirely fair when signed may produce an unfair outcome a decade later. The court’s duty under section 25 of the Matrimonial Causes Act 1973 to consider all the circumstances means no agreement can be entirely protected from challenge. What careful drafting and proper process can do is significantly reduce the court’s reason to depart from the agreed terms.

The conditions that must be met

The rules from Radmacher v Granatino require the court to consider whether the circumstances surrounding the making of the agreement should reduce the weight given to it, and whether it would be fair to hold the parties to those terms. The court looks at several factors.

Whether each party entered the agreement of their own free will, without undue pressure or duress.
Whether both parties had a full appreciation of the agreement’s implications at the time they signed it.
Whether each party received independent legal advice.
Whether there was adequate financial disclosure on both sides.
Whether the agreement was signed so close to the wedding that one party had no real opportunity to negotiate or withdraw.

An agreement signed a fortnight before the wedding, after one party declined to provide financial disclosure, with no independent advice on either side, will carry very little weight. On the other hand, an agreement negotiated over several months, with solicitors on both sides and a detailed schedule of assets, starts from a far stronger position.

Needs and the interests of children

Section 25 of the Matrimonial Causes Act 1973 requires the court to consider all the circumstances of the case, with first consideration given to the welfare of any children of the family. That duty cannot be excluded by contract. A prenuptial agreement that would leave children without adequate housing or support will not be followed, whatever it says.

The Court of Appeal addressed this in Brack v Brack [2018] EWCA Civ 2862, showing that a prenuptial agreement does not automatically confine the court to a purely needs-based award. The starting point is whether the agreement is fair. Where it is, the court can go beyond needs, even where one party argues for a more limited outcome. A spouse who signed an agreement in full knowledge of the other’s wealth cannot automatically retreat to a needs argument simply because the marriage has ended. The agreement will be taken seriously if it was made properly.

When circumstances change

Prenuptial agreements are drafted before the marriage takes place. The marriage that follows may look quite different from the one the parties anticipated. A couple who agreed that neither would make claims on the other’s business assets may not have expected to have three children, one of whom has significant care needs. The business may have grown from a modest enterprise into the family’s primary asset.

The court considers whether, at the time of the divorce, it remains fair to hold a party to terms agreed years or decades earlier. In Kremen v Agrest (No 11) [2012] EWHC 45 (Fam), Mostyn J reviewed the circumstances in which changed circumstances could justify departing from a post-nuptial agreement. The arrival of children, a dramatic change in the parties’ financial position, and a long marriage during which the agreement was never reviewed were all identified as factors weighing against strict enforcement. Couples whose circumstances have changed materially since signing should consider whether a review is overdue. Askews’ family law solicitors advise on both prenuptial and post-nuptial arrangements.

Ring-fencing pre-marital and inherited wealth

The courts have shown a consistent willingness to respect agreements that ring-fence assets the parties brought into the marriage. In Radmacher v Granatino, the agreement was intended to protect the wife’s very substantial inherited wealth. The Supreme Court gave it decisive weight. The same approach has been taken in cases involving family businesses or property held by one party long before the relationship began.

Ring-fencing provisions work best where the asset is clearly identified in the agreement, the other party understands what they were agreeing to exclude, and both parties have had independent advice at the time. Where those conditions are met, a court asked to depart from the agreement will need a compelling reason to do so.

Final words

Prenuptial agreements work best when both parties have engaged with them honestly, received proper advice, and revisited their terms as the marriage develops. An agreement that was carefully made and kept current will carry significant weight at a financial remedy hearing. One that was rushed, one-sided, or never reviewed is far more exposed to challenge. The law does not look for reasons to override a fair agreement. It does, however, look carefully at whether the agreement was fair in the first place, and whether it remains fair now.

Frequently asked questions

Is a prenuptial agreement legally binding in England and Wales?

No, a prenuptial agreement is not a legally binding contract in English law. The court retains jurisdiction to make whatever financial remedy order it considers fair. Following Radmacher v Granatino [2010] UKSC 42, an agreement freely entered into by both parties with a full appreciation of its implications will be given decisive weight unless it would be unfair to hold the parties to it. That falls short of binding, but it is a powerful starting position.

What makes a prenuptial agreement more likely to be followed?

The agreement is more likely to be followed where both parties received independent legal advice, there was full financial disclosure on both sides, it was signed well in advance of the wedding, and neither party was under pressure to accept the terms. An agreement ring-fencing specific pre-marital or inherited assets, where both parties clearly understood what they were giving up, stands the strongest chance of being respected by a court applying the Matrimonial Causes Act 1973 framework.

Can a prenuptial agreement prevent a spouse from receiving any financial provision?

Not where doing so would leave that spouse unable to meet their reasonable needs. Courts will not apply an agreement that produces a manifestly unfair outcome, and the welfare of any children of the family is a consideration that no agreement can override. An agreement can reduce or redirect what a spouse receives. It cannot leave them in genuine hardship.

What should someone do if their prenuptial agreement was not reviewed after they had children?

Seek a review with a family solicitor as soon as possible. The arrival of children is one of the most common reasons a court will depart from prenuptial terms, particularly where one party has significantly reduced their earning capacity to provide care. A post-nuptial agreement can restate and update the original terms. Askews’ family law team advises on both arrangements.

This article is provided for general information only and does not constitute legal advice. It reflects the law of England and Wales as at 23rd April 2026. Specific legal advice should be obtained before acting on anything contained here. Askews Legal LLP is authorised and regulated by the Solicitors Regulation Authority.