Are prenups legally binding in the UK?

What a prenup does and does not do in England and Wales

A prenuptial agreement is a written contract, made before a marriage or civil partnership, setting out how property, income and pensions are divided if the relationship ends. The court is not obliged to follow it and not free to ignore it.

A prenup is open only to couples who marry or form a civil partnership, so it does nothing for cohabiting couples. A couple who agree how to divide money and property still need a consent order to make it binding, so a prenup takes effect through the consent order.

Section 34(1)(a), the clause that is always void

Section 34(1)(a) of the Matrimonial Causes Act 1973 provides that where a maintenance agreement includes a provision purporting to restrict any right to apply to a court for an order containing financial arrangements, that provision is void. Section 34(1)(b) leaves the rest standing between the couple, which is not the same as binding a judge.

Section 34(2) defines a maintenance agreement as an agreement in writing between the parties to a marriage. MacLeod v MacLeod read that as catching an agreement signed after the wedding but not one signed before, and Radmacher left the question to Parliament. The bar on ousting the court does not depend on the answer. A couple can agree what they like about their money and cannot agree that a judge will never look at it, which is why a prenup carries weight rather than binds.

Radmacher v Granatino, the test the courts apply

Radmacher (formerly Granatino) v Granatino [2010] UKSC 42 was decided on 20 October 2010 by a panel of nine, Lady Hale dissenting alone.

Paragraph 75 carries the test. A court should give effect to a nuptial agreement “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 it. Paragraph 2 sets the boundary. The court, though not obliged to follow an agreement, must give it appropriate weight.

The facts of Radmacher, no advice, no disclosure, no written translation

The couple married in London on 28 November 1998. The agreement is dated 4 August 1998, roughly four months earlier, and was executed before a German notary near Dusseldorf. A draft clause requiring each party to state the approximate value of their assets was deleted at the wife’s request, the husband had no written translation of the German document, and he took no independent legal advice. The notary went through the terms with them in English before they signed.

It was upheld regardless. At first instance Baron J awarded him £5,560,000, enough for £100,000 a year for life and a London home. The Court of Appeal gave the agreement decisive weight and limited provision to his role as father, and the Supreme Court found no error of principle.

What reduces the weight a court gives an agreement

Paragraph 71 puts vitiating factors first, meaning duress, fraud and misrepresentation. Undue pressure short of duress is likely to eliminate the weight given to an agreement, as is exploiting a dominant position to secure an unfair advantage.

Disclosure and legal advice are evidence, not conditions. Paragraph 69 asks whether there was any material lack of disclosure, information or advice, and a party who understood the implications but was indifferent to the other’s asset detail gives no reason to reduce it. Paragraph 78 gives the reason weight is granted at all, respect for individual autonomy.

Paragraphs 81 and 82 sort the outcome by strand.

Strand	How an agreement fares
Needs	Most likely to make it unfair to hold the parties to it, since neither is likely to have intended real need on one side
Compensation	The same, where one party gave something up for the marriage and the agreement allows nothing
Sharing	Where each can meet their own needs, the strand a court is most likely to order in the agreement’s terms

Helliwell v Entwistle, non-disclosure of 73% of a fortune

Helliwell v Entwistle [2025] EWCA Civ 1055 was handed down on 31 July 2025. The prenup was a drop hands agreement giving the husband nothing, upheld at first instance with a lump sum of £400,000.

The wife disclosed assets recorded in the judgment as £18,206,735 out of £66,085,535, leaving £47,878,800 undisclosed, so 27% was shown and 73% was not. The Court of Appeal held that deliberate non-disclosure on that scale was fraudulent and vitiated the agreement.

Paragraph 122 records that, absent a statutory scheme, Radmacher continues to bind the Court of Appeal, and that disclosure and legal advice are desirable but not essential. Paragraph 125 adds that the agreement was not produced for the husband to sign until the morning of the wedding, which on those facts would not itself have vitiated it, though the court called that clearly highly undesirable.

Standish v Standish, when ringfenced property becomes shareable

A prenup is usually drafted to keep pre-marriage or inherited wealth outside the pot. Standish v Standish [2025] UKSC 26, decided on 2 July 2025, shows how it ends up inside. Paragraphs 51 and 52 hold that non-matrimonial property becomes matrimonial through matrimonialisation, which rests on the parties treating an asset as shared over time. On those facts the Court of Appeal held 75% of the assets transferred in 2017 non-matrimonial, put the property subject to sharing at £50.48 million and gave the wife approximately £25 million against approximately £107 million, and the Supreme Court dismissed the appeal.

Child maintenance, section 9(4) and the welfare of the children

Section 9(4) of the Child Support Act 1991 makes void any provision purporting to restrict the right to apply for a maintenance calculation. It extends to England, Wales and Scotland, and Article 11(4) of the Child Support (Northern Ireland) Order 1991 is in identical terms.

Inside a divorce, section 25(1) makes the welfare of any child of the family under 18 the court’s first consideration, ahead of the eight factors in section 25(2). Section 35 lets a court vary or revoke the arrangements in a subsisting maintenance agreement where circumstances have changed, including a change the parties foresaw.

Qualifying nuptial agreements, the Ministry of Justice proposal

The position may not hold. The consultation A fairer end to relationships ran from 5 June 2026 to 14 August 2026, covers England and Wales only, and proposes a qualifying nuptial agreement enforceable as a contract and outside the court’s usual discretionary redistribution, subject to five safeguards.

Proposed safeguard	What it would require
Contract validity	Valid as a contract, with no undue influence and no misrepresentation
Form	Executed as a deed, both parties signing a statement that they understand it limits the court’s discretion
Timing	Not made within the 28 days immediately before the wedding or civil partnership
Disclosure	Material information about the other party’s finances, disclosed at the time
Legal advice	Independent legal advice for each party signing

Neither the disclosure nor the advice could be waived, and a qualifying agreement still could not contract out of financial needs or children’s needs. The Law Commission recommended the same structure in Matrimonial Property, Needs and Agreements in February 2014 and still awaits the Government’s response.

Prenups in Scotland and Northern Ireland

	England and Wales	Scotland	Northern Ireland
Governing statute	Matrimonial Causes Act 1973	Family Law (Scotland) Act 1985	Matrimonial Causes (NI) Order 1978
Clause barring the court	Void, section 34(1)(a)	No equivalent, section 16(4) voids only a clause excluding set-aside	Void, Article 36(1)(a)
Test on the agreement	Fair to hold the parties to it at the breakdown	Fair and reasonable when entered into	Article 27 factors
The financial application	Financial remedy	Financial provision	Ancillary relief
Fee to start the divorce	£628	£156 simplified, £191 ordinary	£326 to seal the petition
Regulator	Solicitors Regulation Authority	Law Society of Scotland	Law Society of Northern Ireland

The English fee comes from the HMCTS list, form EX50.

Scotland, fair and reasonable when it was signed

Section 16(1)(b) of the Family Law (Scotland) Act 1985 governs an agreement on financial provision on divorce or dissolution. A court may set it aside or vary a term only where it was not fair and reasonable at the time it was entered into, so fairness is judged at signature rather than at the breakdown, the reverse of Radmacher. Section 16(4) voids only a term excluding that right of set-aside, with no Scottish counterpart to section 34(1)(a).

Much of what an English prenup does is statutory here. Section 10(4) excludes from matrimonial property anything acquired by gift or succession from a third party, and property owned before the marriage other than a family home. Section 10(6)(a) then makes the terms of an agreement on dividing matrimonial property a special circumstance justifying an unequal share.

The document is a minute of agreement, registered by a solicitor in the Books of Council and Session, which mygov.scot describes as legally binding and enforceable in the same way as a court order. Registration needs a self-proving deed under section 6 of the Requirements of Writing (Scotland) Act 1995. Sheriff court fees from 1 April 2026 are £156 for a simplified divorce and £191 for an ordinary action. Because the minute is registered rather than approved by a judge, the drafting and the registering sit with the solicitor rather than the sheriff court, which is what a firm on the Edinburgh list is instructed to do.

Northern Ireland, Article 36 and ancillary relief

The same answer arrives through a different statute. Article 36(1)(a) of the Matrimonial Causes (Northern Ireland) Order 1978 voids any provision in a maintenance agreement purporting to restrict the right to apply to a court, and Article 27 lists the matters the court must weigh, in the same order as section 25(2). Article 37 lets it alter a subsisting agreement on changed circumstances or where it fails a child.

The vocabulary is older. The County Court and the High Court deal with divorce, the applicant is the petitioner, and a decree nisi is followed at least six weeks and one day later by a decree absolute. A petition must still state a ground, from two years’ separation with consent, five years’ separation, unreasonable behaviour, adultery or desertion, and none can be brought in the first two years of the marriage. The documents lodged with it include any agreements the petitioner wishes to be made a rule of court.

Under the Family Proceedings Fees (Amendment) Order (Northern Ireland) 2026, from 1 April 2026 sealing a petition costs £326, a notice of application for ancillary relief £488 in the High Court or £407 in the County Court, and the certificate of decree absolute £123. The Ministry of Justice consultation covers England and Wales only, so nothing in it moves Belfast.