If you have read that prenuptial agreements now “carry significant weight” in England & Wales, you have Radmacher v Granatino to thank. The 2010 Supreme Court decision is the single most important case on prenups in this country: it is the reason a properly made agreement is respected by the courts today, rather than brushed aside. So it is well worth understanding what the case actually decided, why it changed the law, and what it means for the agreement you are thinking of making.
This guide explains the case in plain English – the facts, the ruling, the famous test it laid down, and the practical lessons you can take from it – and shows how it connects to whether prenups are legally binding in the UK more generally.
The law before Radmacher
For most of the twentieth century, English courts were openly hostile to prenuptial agreements. They were treated as contrary to public policy – the reasoning being that a couple should not be able to contemplate, let alone plan for, the breakdown of their own marriage, and that only the court could decide what was fair on divorce. An agreement might be looked at as one factor, but it carried little real weight. Couples who signed a prenup had no assurance it would count for anything at all.
Attitudes shifted gradually as society changed and cases such as White v White (2000) and Miller; McFarlane (2006) modernised how the courts approached financial settlements. But it took Radmacher to state clearly that a properly made agreement should be respected. It is the turning point in the story told in our guide to the key UK prenup court cases.
What the case was about
Katrin Radmacher, a German heiress from a wealthy paper-manufacturing family, and Nicolas Granatino, a French former investment banker, signed a prenuptial agreement in Germany before marrying in London in 1998. The agreement provided that neither would make any financial claim against the other if the marriage ended. Under German and French law, where such agreements are commonplace and binding, this was entirely normal.
The couple had two children and lived, for a time, a comfortable life largely funded by Ms Radmacher’s family wealth. Mr Granatino later left banking to become an academic researcher on a far lower income. When the marriage broke down after around eight years, he applied to the English courts for a substantial financial award. Ms Radmacher argued that the court should hold them both to the agreement they had freely signed.
What the Supreme Court decided
The Supreme Court, by a majority, sided broadly with Ms Radmacher and set out the principle that still governs prenups today. In its most quoted words, a court should give effect to a nuptial agreement that is freely entered into by each party with a full appreciation of its implications, unless in the circumstances prevailing it would not be fair to hold the parties to their agreement.
That single sentence is the foundation of the modern law. Notice its structure: the starting point is now to respect the agreement, and the burden shifts to the partner who wants to escape it to show why it would be unfair. The award to Mr Granatino was sharply reduced from what he had sought, and the provision he did receive was made largely in his role as the father caring for the couple’s children – housing and support during their childhood – rather than as long-term provision for himself.
The three strands of the Radmacher test
It helps to break the famous sentence into the three things a court is really asking:
- Was it freely entered into? No duress, undue pressure or exploitation of one partner by the other.
- Did each party have a full appreciation of its implications? This is where full and frank financial disclosure and independent legal advice come in – you cannot appreciate what you are giving up if you do not know what the other person has, or understand the effect of the document.
- Would it be fair to hold them to it? Even a freely made, fully understood agreement gives way where enforcing it would be unfair – especially where it fails to meet needs or provide for children.
Get all three right and your agreement sits squarely inside the Radmacher principle. That is precisely why the modern best-practice checklist in what to include in a prenup looks the way it does.
Two big ideas: autonomy and the fairness override
Behind the test lie two ideas worth naming. The first is autonomy: the court now accepts that adults are entitled to decide their own financial affairs, and that respecting a couple’s considered choice is itself part of a fair outcome. The second is the fairness override: that respect is not unlimited. Where holding a couple to their bargain would leave one of them, or their children, unable to meet reasonable needs, fairness wins. These two ideas pull in opposite directions, and every later case is essentially about where the line falls between them – a theme we trace in when is a prenup unfair?
What Radmacher did not do
It is just as important to be clear about the limits of the decision. Radmacher did not make prenups automatically binding – they still are not (see are prenups legally binding in the UK?). The court kept its discretion under the Matrimonial Causes Act 1973, and it preserved the two backstops it can never sign away: meeting needs and providing for children. What changed was the weight a fair agreement carries, not the removal of the safety net.
Why it matters for your agreement
The practical message of Radmacher is encouraging: if you and your partner make your agreement the right way, a court will very probably hold you to it. “The right way” means the very things the case highlighted – full disclosure, independent advice for each of you, signing in good time rather than under wedding-week pressure, and fair terms that do not leave anyone in need. It also shaped what a prenup should include: a clear, full picture of each partner’s finances and provision that a court can regard as fair.
Radmacher in the cases that followed
Later decisions have applied and refined the principle rather than overturned it. In Brack v Brack (2018) the Court of Appeal stressed that even a valid agreement does not force the court into a fixed outcome – the discretion remains. In Ipekçi v McConnell (2019) an agreement was given no weight because disclosure and advice were lacking and enforcing it would have left a partner in need. Read together with Radmacher, the message is consistent: fair, well-made agreements are respected; corner-cutting ones are not. See key UK prenup court cases for the wider picture and can a prenup be overturned? for how a challenge plays out.
Radmacher v Granatino: the lasting principle
The lasting legacy of Radmacher v Granatino is a single sentence the courts still apply: give effect to a freely entered agreement that both partners fully understood, unless it would be unfair to hold them to it. It did not make prenups automatically binding, and it did not remove the court’s duty to meet needs and provide for children – but it shifted the starting point firmly towards respecting a fair, well-made agreement. If you take one thing from the case, let it be this: the more carefully you make your prenup, the more certainty it gives you.
What the judgment said in detail
Three parts of the judgment do most of the work. The first swept away the old rule. The court held that the principle that an agreement providing for a future separation was contrary to public policy was obsolete and should no longer be applied, which removed the reason earlier courts had given for ignoring prenups altogether. The second set the test that every later case quotes: the court should give effect to a nuptial agreement that is freely entered into by each party with a full appreciation of its implications unless in the circumstances prevailing it would not be fair to hold the parties to their agreement. The third explained what each part of that test looks at. On "freely entered into", duress, fraud and misrepresentation negate an agreement, but lesser pressure, one party's exploitation of a dominant position, and the parties' emotional state, age and maturity at the time all reduce its weight. On "full appreciation", disclosure and independent legal advice are the evidence, though neither is an absolute precondition. On fairness, the court named the situations most likely to make holding the parties to the agreement unfair: real need, the reasonable requirements of children, and an unaddressed claim to compensation for a career given up.
Two further features are easily missed. The court gave weight to the fact that the agreement would have been binding under German law, treating that as evidence the parties intended it to be effective, which is why foreign agreements are now judged on the same footing as English ones. And the court applied its own test to Mr Granatino's claim under section 25 of the Matrimonial Causes Act 1973, cutting the award to provision for his role as the children's father. The cases since, from Versteegh v Versteegh to HD v WB, have applied that framework without altering it.
Radmacher v Granatino: FAQs
Did Radmacher make prenups binding in the UK?
No. It made a fair, properly made agreement carry significant weight, but not automatic legal force – the court keeps its discretion (see are prenups legally binding?).
What is the Radmacher test in one line?
A court should give effect to an agreement freely entered into by each party with a full appreciation of its implications, unless it would be unfair to hold them to it.
Does Radmacher still apply today?
Yes – it remains the leading authority and has been applied in every significant prenup case since (see key UK prenup court cases).
Why did Mr Granatino still receive something?
Provision was made largely for his role caring for the couple’s children – the court will always look after children and meet needs, whatever an agreement says.
How do I make my prenup fit the Radmacher principle?
Exchange full disclosure, take independent legal advice each, sign in good time, and agree fair terms – the steps set out in what to include in a prenup.
Was Radmacher a divorce case or a prenup case?
Both – it was a divorce in which the central question was how much weight to give the prenup the couple had signed, and the answer reshaped the law for everyone since.
Does Radmacher apply to postnuptial agreements too?
Yes – the case concerned nuptial agreements generally, and the same “freely entered into and fair to enforce” principle applies to a postnup signed after the wedding.
Could a future law override Radmacher?
It could – the Law Commission proposed qualifying nuptial agreements that would make a properly made agreement binding, but that reform is not yet law, so Radmacher still governs.
Create your prenuptial agreement online
UK Prenup lets couples in England & Wales create a clear, fair prenuptial agreement online from £199, with your document generated instantly as a PDF. See how it works or get started.
UK Prenup is not a law firm and does not provide legal advice. A prenuptial agreement in England & Wales is not automatically binding, and both partners should take independent legal advice before signing.