A prenuptial agreement is often misunderstood. Many believe it predicts failure or hints at mistrust, when in reality, the opposite is true. A prenup is one of the strongest expressions of trust a couple can make. It shows that both partners care enough about their future to plan responsibly, transparently, and fairly. We plan our careers, mortgages, investments, holidays, businesses, and children’s futures, but most couples still enter the most legally binding relationship of their lives without planning the financial partnership that underpins it all.

In England and Wales, the significance of well-drafted, professionally guided prenups has never been greater. Gone are the days when prenups were dismissed as “American ideas” or seen as optional wish lists. Today, courts take them seriously and often give them decisive weight when drafted correctly. However, their power comes with an important condition: a prenup must be built properly. If an agreement is unfair, vague, rushed, or poorly drafted, the court may disregard it entirely. A prenup that looks protective on paper can become meaningless the moment it is tested, leaving couples exposed to uncertainty, stress, and avoidable legal battles.

This guide explores the most common mistakes that cause prenups to fail and explains why expert legal guidance is the key to ensuring your agreement stands firm in court. If you are considering a prenup or even if you are unsure, this may be the most important information you read before taking another step.

How Courts in England & Wales Assess Prenuptial Agreements

The legal landscape surrounding prenups changed dramatically with the 2010 Supreme Court case Radmacher v Granatino. This landmark decision established that a prenup should be upheld as long as it was entered into freely, with full understanding of its implications, and so long as it remains fair to enforce. These three pillars, freely, understanding and fairness form the foundation upon which every valid prenup stands.

For an agreement to be considered valid, it must be signed voluntarily, without pressure or emotional manipulation. Both parties must fully understand the terms, implications, and consequences of the agreement, which is why legal advice is not just recommended but essential. Finally, the agreement must be fair. A court will not uphold a prenup that leaves one partner destitute, unable to meet basic needs, or bound by unreasonable conditions. Every mistake couples make when drafting a prenup risks weakening one of these pillars. If even one is compromised, the entire agreement becomes vulnerable.

Courts increasingly view prenups as a responsible planning tool. They appreciate that modern couples are often older when they marry, have more complex assets, blended families, businesses, property portfolios, or inheritances to consider. A prenup, when done correctly, reflects maturity, not mistrust. But the courts also remain firm: if a prenup is to be upheld, it must respect these core principles clearly, transparently, and fairly.

The Prenup Mistakes That Destroy Agreements

Below are the mistakes that most commonly lead to prenups being dismissed or significantly weakened in court. Each one has real consequences, but each one is also avoidable with the right support

Mistake #1: Assuming General Financial Knowledge Is Enough

One of the most common and damaging errors couples make is believing that a general understanding of each other’s finances is sufficient. It is not. Prenups in England and Wales require full, frank, and honest financial disclosure. Anything less than complete transparency puts the entire agreement at risk.

Financial disclosure must include:

• all assets (property, savings, investments, shares)
• all liabilities (loans, mortgages, credit
• all income streams (employment, rental income, dividends)
• all pensions
• all business interests or ownership stakes

Courts expect accuracy, transparency, and formal documentation. This means disclosure must be written, recorded, and verifiable, not discussed casually or assumed.

If financial disclosure is incomplete or vague a court may later decide that one partner lacked crucial information or was misled about the true financial picture. If that argument is raised, the prenup can unravel instantly. A claim that one party “did not know what they were agreeing to” can be enough to undermine months of planning.

Legal guidance ensures that every financial detail is properly documented and cross-referenced. A solicitor will create formal asset schedules and ensure that nothing is omitted. This protects both partners and ensures no one can claim they were unaware of the financial implications of what they signed. With proper legal structure, financial disclosure becomes a solid foundation of fairness and evidence.

Mistake #2: Leaving the Prenup Until the Last Minute

Another mistake that frequently destroys prenuptial agreements is timing. Many couples delay discussing or drafting their prenup until the wedding is only days or weeks away. Some believe this avoids awkwardness, while others underestimate how long the process takes. But a last-minute prenup can be fatal to its validity.

The closer a prenup is signed to the wedding date, the easier it becomes for someone to later argue that they were under pressure, too stressed to think clearly, or emotionally overwhelmed.

Courts in England and Wales take timing extremely seriously. The Law Commission recommends signing at least 28 days before the wedding. Signing after this threshold introduces the risk of:

• duress
• undue influence
• emotional pressure
• fear of the wedding falling apart

Even if no actual pressure occurred, the possibility of pressure is enough to harm the agreement.

Solicitors carefully manage the timing of a prenup to ensure that both partners have space to reflect, negotiate, and ask questions. A prenup signed several months before the wedding demonstrates that both partners had time, choice, and clarity. This alone significantly increases the likelihood of the court enforcing it.

Mistake #3: Trying to Use the Same Solicitor for Both Parties

Many couples believe that using one solicitor will make the process simpler, quicker, or cheaper. Unfortunately, it puts the entire agreement at risk. A single solicitor cannot advise both parties because their interests, however aligned personally, may diverge legally.

Without independent legal advice, a court may conclude that:

• one partner did not fully understand the agreement
• one partner was not properly advised
• the negotiation was not balanced
• the playing field was not equal

Independent legal advice is one of the strongest indicators that a prenup was entered into freely and fairly.

When each partner has their own solicitor, they each receive personalised advice. They fully understand every clause, every implication, and every future consequence. This creates a prenup that is robust, respected, and legally defensible. Two solicitors do not cause conflict, they prevent it.

Mistake #4: Including Lifestyle Clauses That Courts Ignore

A common misconception, often fuelled by films and celebrity gossip, is that couples can include lifestyle requirements in their prenup. Some attempt to add clauses about fidelity, communication habits, appearance, or even weight. Others try to predetermine child arrangements or future child maintenance. However, none of these clauses have any legal effect in England and Wales. The courts do not enforce lifestyle rules or clauses relating to children.

Including such clauses can weaken your prenup by making it appear:

• emotionally driven rather than practical
• controlling rather than fair
• unfocused on financial planning

A prenup must remain strictly about financial matters. Solicitors ensure that only legally enforceable clauses are included, those relating to assets, business interests, inheritance protection, property, spousal maintenance, and financial responsibilities.

By keeping the agreement focused and professional, solicitors preserve its credibility and protect it from court scepticism.

Mistake #5: Using Vague or Ambiguous Language

Another common mistake is trying to keep the prenup “flexible” by using vague statements such as:

• “We will divide assets fairly.”
• “We will agree later.”
• “A reasonable amount will be paid.”

Although well intended, vague language makes a prenup vulnerable. Anything unclear invites interpretation, and once a judge must interpret a clause, the purpose of a prenup, to remove uncertainty, is lost.

A strong prenup uses precise, measurable language, such as:

• exact percentages
• defined formulas
• clear definitions of marital vs non-marital property
• specific treatment of inheritances
• identifiable payment triggers

Solicitors ensure clarity, precision, and enforceability. They draft terms that leave no room for confusion or future disagreement.

Why Legal Guidance Is the Only Way to Create a Watertight Prenup

A prenup is not merely a document; it is a structured legal process that requires expertise, strategy, and careful execution. Solicitors act as guides of this process, ensuring couples fully understand the terms of what they are signing up

They ensure:

• full financial disclosure
• independent legal advice for both parties
• precise  drafting
• fairness that aligns with court expectations
• timelines that prevent claims of pressure or duress
• future-proof clauses for children, relocation, or business changes

Without legal guidance, a prenup becomes a fragile document that may collapse under scrutiny. With expert support, it becomes a secure, strategic financial plan built to withstand challenges.

Frequently Asked Questions About Prenups in England & Wales

Secure Your Future With Confidence

A prenuptial agreement is not about predicting the end of a relationship. It is about building a future with clarity, honesty, and shared trust. It ensures that decisions about finances, assets, and security are made together, not left to the discretion of a court. A properly drafted prenup protects your relationship, your peace of mind, and your financial future.

For a prenup to carry real legal weight, it must be drafted properly, disclosed fully, signed freely, reviewed independently, and structured fairly. When these elements come together, the agreement becomes far more than legal paperwork. It becomes a promise, one built to protect you both, built to endure, and built to stand firm if ever tested.

If you value clarity, fairness, and long-term security, a professionally drafted prenuptial agreement is not just beneficial, it is a wise investment in the future you are building together.