What are the Requirements of a Valid Will?

What Are the Requirements of a Valid Will?

For a Will to be legally effective in England and Wales, it must meet strict requirements concerning matters such as age, intention, signing and witnessing. Questions about mental capacity, knowledge and approval, fraud or undue influence can create further grounds for dispute. Lewis Nedas Law advises on preparing legally valid Wills and resolving issues concerning their validity.

Call +44 20 7387 2032 for confidential advice or complete our online contact form to speak to our Wills solicitors in London.

Experienced Wills Solicitors in London

Lewis Nedas Law has provided legal services for more than 40 years. The firm is authorised and regulated by the Solicitors Regulation Authority, SRA number 567461, and has received independent recognition as a Legal 500 Leading Firm 2026 and through inclusion in The Times Best Law Firms 2026.

Our Wills, Trusts and Probate solicitors advise individuals and families on preparing Wills, estate planning, probate and questions concerning the validity of testamentary documents.

We can advise on straightforward estates and more complex arrangements involving substantial assets, trusts, businesses or assets outside England and Wales.

What Makes a Will Valid in England and Wales?

The principal statutory formalities are contained in section 9 of the Wills Act 1837. For most people making a Will in England and Wales, the document must:

The person making the Will is commonly called the testator. A person must usually be aged 18 or over to make a Will. Limited statutory exceptions exist, including particular circumstances involving members of the armed forces and mariners.

Meeting the signing formalities is only part of the legal picture. Questions concerning testamentary capacity, knowledge and approval, undue influence, fraud or forgery can affect whether a purported Will is admitted to probate.

Does a Will Have to Be in Writing?

Yes. A Will needs to be in writing to comply with the ordinary requirements of the Wills Act 1837. A professionally drafted Will can reduce uncertainty over its meaning and create a clearer record of what the person intended.

Legal advice can be particularly useful where family circumstances or assets are complex, there are concerns about a possible future challenge, or the person making the Will may be vulnerable.

How Should a Will Be Signed and Witnessed?

Signing and witnessing mistakes can cause serious problems. The testator should sign the Will, or acknowledge their signature, in the presence of two witnesses who are present at the same time. Each witness then signs or acknowledges their signature in the testator's presence. The law does not ordinarily require the witnesses to sign in each other's presence.

Choosing appropriate witnesses is equally significant. A beneficiary should not normally witness a Will. Nor should the spouse or civil partner of a beneficiary. Under section 15 of the Wills Act 1837, having an interested person act as a witness does not ordinarily invalidate the entire Will. Instead, a gift to that witness, or their spouse or civil partner, may be void. This is an important distinction and one reason independent witnesses are preferable.

What Is Testamentary Capacity?

A person needs the required mental capacity to make a valid Will. The traditional legal test for testamentary capacity derives from the case of Banks v Goodfellow (1870). Broadly, the person making the Will should understand:

Capacity is a legal question assessed in the circumstances existing when the Will is made. Age, illness or a medical diagnosis does not automatically mean that a person lacks testamentary capacity. Where capacity may later be questioned, obtaining appropriate legal and medical input when the Will is prepared can provide valuable evidence about the circumstances in which it was made.

What Does Knowledge and Approval Mean?

A person making a Will must know and approve its contents. In practical terms, the document should reflect the testator's intentions and they should understand what they are signing.

Questions about knowledge and approval can arise where, for example, a Will contains unexpected provisions, the testator had difficulties reading or understanding the document, or someone benefiting substantially from the Will was closely involved in its preparation. Solicitor-led preparation can provide a contemporaneous record of the instructions received, advice given and steps taken when the Will was signed.

Must a Will Be Made Voluntarily?

A Will should represent the testator's own intentions. A Will may be challenged where it is alleged that the testator was subjected to undue influence. In the probate context, this involves more than persuasion or family pressure. The allegation concerns coercion that overpowered the testator's own wishes.

Fraud and forgery can provide separate grounds for challenging a purported Will. These are fact-sensitive issues and anyone concerned about the circumstances surrounding a Will should seek legal advice.

What Happens if a Will Is Invalid?

The consequences depend on the circumstances. If the deceased previously made an earlier Will that remains valid and was not effectively revoked, that document may govern the estate. If there is no valid Will capable of taking effect, the estate may pass under the intestacy rules.

It is not accurate to assume that every defect automatically means the whole estate becomes intestate. Some issues may affect a particular gift rather than invalidate the entire Will. Where validity is disputed, legal advice can help executors, beneficiaries and family members establish which document governs the estate and what steps should be taken before assets are distributed.

Can I Change My Will?

A Will can be changed after it has been executed, but amendments need to comply with the relevant legal requirements. A codicil is a separate document used to amend an existing Will. It needs to be executed using the same signing and witnessing formalities as a Will.

For substantial changes, preparing a new Will may provide greater clarity than relying on several codicils. You should not simply write amendments onto a signed Will. Informal alterations can create uncertainty about whether a change is legally effective.

How Can a Will Be Revoked?

One common method is making a new Will containing an express revocation clause. Under the Wills Act 1837, a Will can also be revoked through destruction where the statutory requirements are satisfied. This requires more than a document simply being damaged or lost. The relevant act must be carried out by the testator, or by another person in the testator's presence and at their direction, with the intention of revoking the Will.

Questions surrounding missing or destroyed Wills can become legally complex. The existence of photocopies does not by itself answer whether the original Will remained legally effective when the testator died. Professional advice should be sought where the original Will cannot be located.

Does Marriage Revoke a Will?

Marriage or entering a civil partnership can have major consequences for an existing Will. Under the law of England and Wales, marriage or civil partnership will usually revoke an existing Will. An important exception can apply where a Will has been made in contemplation of a particular marriage or civil partnership and drafted so that the relevant statutory requirements are satisfied.

Anyone planning to marry or enter a civil partnership should consider reviewing their Will. Divorce has different consequences and does not simply revoke the entire Will. Reviewing estate planning following separation or divorce is sensible where existing provisions no longer reflect your intentions.

What About Wills Involving Overseas Assets?

International estates can raise questions that go beyond the formal requirements applying to a domestic Will. Issues may include:

Lewis Nedas Law has experience advising clients with international connections and estates containing overseas assets. Specialist advice can help identify which legal systems may apply and whether separate advice is required in another jurisdiction.

Why Choose Lewis Nedas Law?

Frequently Asked Questions About Valid Wills