Signing a prenup is one of the more practical steps a couple can take before marriage, yet many people rush the process or misunderstand what makes an agreement hold up in court. The result is often a document that looks official but carries little weight if it’s ever tested.
This article sets out the biggest mistakes couples make when signing a prenup, along with how to avoid each one. The same principles apply whether the agreement is being drawn up before the wedding or as a postnuptial agreement afterwards.
Knowing what keeps a prenup enforceable often comes down to avoiding a handful of common errors, most of which are entirely avoidable with enough preparation time.
Waiting Too Long to Start the Process
Timing is one of the most overlooked parts of the prenup process, and many couples leave it too late, sometimes finalising an agreement just days before the wedding. Courts in England and Wales look closely at when an agreement was signed, and a rushed timeline can suggest one party felt pressured or didn’t have enough time to consider the terms.
Guidance on making your prenup enforceable from Stowe Family Law generally recommends allowing at least 28 days between drafting and signing, giving both parties time to review the terms and get independent legal advice. A rushed timeline can directly undermine the agreement’s effectiveness if the matter ever reaches court, particularly if one person later claims they felt pressured into signing.
Skipping Independent Legal Advice
Separate legal advice for both parties is one of the strongest indicators that a prenuptial agreement was entered into freely and with full understanding. UK case law has confirmed that a lack of independent advice weakens one party’s understanding of what they’re agreeing to, increasing the likelihood the agreement could be set aside.
If the same solicitor acts for both parties, or one person signs without any legal input, it becomes far easier for a judge to find there was a lack of genuine consent. For a second marriage prenup, this matters even more, since asset structures are often more complicated, with property from an earlier marriage, business interests or inheritance considerations all needing separate attention.
Failing to Disclose All Financial Information
Full financial disclosure is a requirement, not a suggestion, and both parties need to share a complete picture of their finances before signing, including assets, debts, property, savings, retirement accounts and business interests. Incomplete disclosure is a common reason courts decline to uphold a prenuptial agreement, and if key information later turns out to have been withheld, the entire agreement can be called into question.
Using Vague or Unenforceable Terms
Wording matters as much as process, and vague clauses or terms courts won’t uphold can undermine a prenup even if everything else was handled correctly. Provisions about child arrangements or child support are a frequent source of this problem, since courts in England and Wales decide these matters based on a child’s welfare at the time, not on what parents agreed before marriage.
DIY or template agreements frequently contain errors like this, and working with a qualified family law solicitor considerably reduces the risk of terms that won’t hold up.
Not Revisiting the Agreement After Major Life Changes
A prenup reflects the situation at the time it was signed, and an agreement drawn up before children, inheritance or a major financial shift may no longer be accurate or fair. Couples who experience significant change after marriage can consider a postnuptial agreement instead, which works in a similar way but is signed after the wedding, allowing terms to be updated to reflect the couple’s current situation.
This matters particularly for blended families and second marriages, where reviewing the original agreement as assets grow or family circumstances shift is a practical step rather than an optional one.
Getting Your Prenup Right From the Start
Avoiding these mistakes won’t guarantee an agreement is never challenged, but it puts couples in a considerably stronger position if it ever is. Every situation is different, so which mistakes matter most will depend on the assets, timeline and family circumstances involved. Get in touch with a specialist family law team to talk through what your prenup or postnuptial agreement needs to cover.
