This guide is maintained as a current resource for September 2026 and covers only the laws of England and Wales. Information is for general guidance, not legal advice. Consult a qualified solicitor for advice specific to your situation.
Learn the common mistakes that can invalidate a will in England and Wales, including improper execution, lack of capacity, undue influence, fraud, and drafting errors, and understand how these affect estate distribution and potential disputes.
Writing a valid will is essential for ensuring a person's estate is distributed according to their wishes after death. In England and Wales, strict legal requirements must be met for a will to be legally effective. If these requirements are not complied with, the will can be invalidated, leading to unintended results such as the estate passing under intestacy rules, costly legal disputes, and disappointment for intended beneficiaries. This article explains the most common mistakes that can render a will invalid, drawing on current law and authoritative sources.
What Makes a Will Valid in Law?
Under section 9 of the Wills Act 1837, a will must meet formal requirements to be valid. These include being in writing, signed by the testator (or by someone directed by the testator), and witnessed by two independent adult witnesses present at the same time, who then attest and sign the document.
Even if a will appears to express the testator's wishes, failing to follow these fundamental rules can lead to invalidity. Below are the most frequent errors that cause problems in practice.
1. Failing to Follow Formal Execution Requirements
A critical cause of invalid wills is failure to meet the formalities prescribed by the Wills Act:
- A will must be in writing. Oral wills are not recognised except extremely rarely in limited statutory exceptions.
- The testator must sign the will with the intention of giving it effect.
- The signature must be made or acknowledged in the presence of two witnesses present together.
- Each witness must then sign in the testator's presence.
Errors such as having only one witness, witnesses who are beneficiaries or married to beneficiaries, or signing outside the presence of the required witnesses all risk invalidating the will or at least voiding specific gifts.
2. Improper Witnessing or Ineligible Witnesses
Witnesses play a central role in confirming that the will was properly executed:
- Witnesses must be adults (over 18) and independent (not benefitting under the will or connected to someone who does).
- If a beneficiary or their spouse/civil partner acts as a witness, the gift to that person is void, even though the remainder of the will may still stand.
Using a beneficiary as a witness is a common error in homemade wills or DIY templates.
3. Lack of Testamentary Capacity
A will can be invalid if the testator did not have the required mental capacity at the time of signing. A person must:
- Understand the nature and effect of making a will,
- Appreciate the extent of their estate,
- Recognise who might reasonably be expected to benefit,
- Be free from any mental disorder that would influence decisions.
If a will is executed by someone lacking capacity, it may be subject to challenge in court, with the challenger required to provide evidence such as medical records.
4. Undue Influence or Duress
A will must reflect the testator's free and voluntary decisions. Undue influence arises where someone exerts pressure, persuasion or coercion to alter the terms of a will in their favour.
Examples include family members, carers, or advisors who exert inappropriate influence on an elderly or dependent testator. If undue influence is proven, the will (or particular provisions) can be set aside by a court.
5. Fraud or Forgery
Deliberate deception surrounding the execution of a will can render it invalid:
- Forgery includes forging the testator's signature or creating a will without their consent.
- Fraudulent calumny involves misleading the testator about facts that affect their decisions.
Proving fraud or forgery typically requires clear evidence, such as forensic analysis of signatures or testimony showing the document's contents were falsified.
6. Errors in Drafting and Ambiguity
Vague or unclear language may not automatically invalidate a will, but it can cause disputes and may lead courts to interpret provisions contrary to the testator's intention. Unclear instructions such as imprecise descriptions of beneficiaries or assets increase the risk of litigation and delay estate administration.
Examples include general terms like “my personal effects” without clarifying what items are included, or failing to describe assets by address or account details.
7. Failing to Revoke or Update Previous Wills
Making a new will does not automatically revoke an earlier will unless it includes a revocation clause. If a previous will remains extant, it may create ambiguity or result in competing documents that courts must reconcile.
Failing to update a will after major life events (marriage, divorce, birth of children) can also lead to unintended outcomes, as marriage may automatically revoke an earlier will without clear instructions.
8. Destroying or Losing the Original Will
Physical destruction of a will with intent to revoke it results in invalidation. A lost or destroyed original will is generally presumed revoked unless strong evidence proves it was misplaced rather than deliberately destroyed. A copy alone is seldom sufficient without additional proof of authenticity.
Practical Consequences of an Invalid Will
If a will is declared invalid:
- A previous valid will may be revived.
- If there is no valid will, the estate passes under intestacy rules, which may not reflect the deceased's wishes.
- Family disputes and costly litigation can arise, reducing the value available to beneficiaries.
In addition, errors can give rise to professional negligence claims against legal advisers who drafted or witnessed the flawed document.
Key Takeaways
Most wills are invalidated by procedural errors or failure to comply with strict legal requirements. The most common mistakes include:
- Improper execution and witnessing.
- Testator lacking capacity or acting under undue influence.
- Fraud, forgery or unclear drafting.
- Failure to revoke previous wills or correctly manage changes.
Ensuring compliance with formalities and seeking professional input significantly reduces the risk of invalidation, helping to protect the testator's intentions and avoid disputes.
