19.1 Validity of Wills and Codicils

A will is a document that takes effect on death. Until then the testator can revoke or replace it, provided they still have capacity. For SQE1 FLK2, validity is not a single yes-or-no instinct about fairness. You advise on five linked questions: Did the testator have testamentary capacity? Did they know and approve the contents? Was their will overborne by duress or undue influence? Were the formalities in section 9 of the Wills Act 1837 met (unless a privileged will applies)? Who has to prove which of those points if someone challenges the document? This independent OpenExamPrep section covers those FLK2 topics for England and Wales.

Who may make a will

Section 7 of the Wills Act 1837 requires the testator to be 18 or over. The practical exception is a privileged will under section 11: a soldier in actual military service, or a mariner or seaman at sea, may make an informal will, including while under 18 and without section 9 witnesses. A company cannot make a will. An attorney under a lasting power of attorney cannot execute a will for the donor. If the donor has lost testamentary capacity, the only court route to a post-loss will is a statutory will in the Court of Protection (Mental Capacity Act 2005, ss.16 and 18). That is a different instrument from a lifetime attorney signing the donor's name.

A codicil is a testamentary instrument that adds to, amends, or partly revokes a will. It must itself be valid. Every point in this section that applies to a will applies to a codicil: capacity, knowledge and approval, absence of coercion, and section 9 (unless privileged).

Testamentary capacity: Banks v Goodfellow

The working test is still Banks v Goodfellow (1870) LR 5 QB 549. The testator must:

1. understand the nature of the act and its effects (they are making a will that will dispose of property on death);
2. understand the extent of the property of which they are disposing (a working grasp of the estate, not a solicitor's inventory);
3. comprehend and appreciate the claims to which they ought to give effect (who might reasonably expect provision, even if the testator then chooses to exclude them);
4. not be subject to a disorder of the mind that poisons their affections, perverts their sense of right, or prevents the exercise of their natural faculties in disposing of the estate.

A delusion defeats the will only if it drove the disposition. A person with a diagnosed illness can still have a lucid interval sufficient for a will. Recent bereavement, heavy medication, or overwhelming grief can destroy capacity on the facts (Key v Key [2010] EWHC 408 (Ch)). Eccentric gifts, or gifts that children consider unfair, do not by themselves prove incapacity. English law allows a capable testator to cut a child out.

The Mental Capacity Act 2005 test (understand, retain, use or weigh, communicate) is the everyday test for lasting powers of attorney and many lifetime decisions. It does not replace Banks v Goodfellow when the issue is whether a will is valid. Clitheroe v Bond [2021] EWHC 110 (Ch) confirmed that the probate courts still apply Banks v Goodfellow. Do not advise that someone who "has MCA capacity" can automatically make a will, or that an MCA finding of incapacity is automatically fatal without applying the Banks questions to that will.

Parker v Felgate (1883) 8 PD 171 is a limited safety valve. If the testator had capacity when they gave instructions, the executed document carries out those instructions, and at execution they understood they were signing a will prepared from those earlier instructions, the will can stand even if they could no longer follow every clause on the signing day.

The Golden Rule associated with Kenward v Adams (1975) is professional practice, not a validity rule. Where the testator is elderly or seriously ill, a solicitor should consider asking a medical practitioner to assess capacity and, where practical, to witness the will. Skipping that step does not invalidate the will. Following it makes a later challenge harder to run and is relevant to a negligence claim against the solicitor.

Example. Priya, 82, has moderate dementia. On a good morning she can describe her flat, her savings, and her two children. She tells her solicitor she wants everything to go to her daughter, who cares for her, and nothing to her son, who she knows is wealthy. She understands that this document is a will and that her son may be unhappy. Banks v Goodfellow can be satisfied even if she would struggle with a lasting-power-of-attorney interview later the same day. If instead she insists her son is already dead (he is not) and that is why he takes nothing, the delusion may poison the will.

Knowledge and approval

Capacity and knowledge and approval are different requirements. A capable testator may still sign a document they did not know and approve: pages switched after they read a draft; a will that does not match their instructions; a long English will signed by a testator who cannot read English and had no proper explanation; a signing session in which they were too distressed to take the contents in.

Where the testator had capacity and the will was duly executed, the court usually presumes knowledge and approval. That presumption can be displaced by suspicious circumstances. Classic suspicion includes a will prepared by a person who takes a large benefit, a solicitor-beneficiary, a sudden break from a long-standing pattern of gifts with no independent advice, or a testator who could not read the language of the will.

Once suspicion is raised, the person propounding the will (usually the executor seeking a grant) must prove that the testator knew and approved the contents. Reading the will aloud is strong evidence, but it is not conclusive. In Gill v Woodall [2010] EWCA Civ 1430 a will read to an agoraphobic testator still failed on knowledge and approval on those facts. Barry v Butlin (1838) 2 Moo PC 480 and Wintle v Nye [1959] 1 WLR 284 show how closely the court scrutinises a will that benefits the drafter.

Example. Omar, a solicitor, prepares his uncle's will leaving Omar half the residue. The uncle had capacity and two independent witnesses signed. Omar still has to prove knowledge and approval. Sensible practice is independent advice for the uncle, a full attendance note, and evidence that the uncle read or had explained to him the gift to Omar.

Duress and undue influence

Undue influence in probate means coercion that overbears the testator's own wishes so that the document is not their will (Hall v Hall (1868); Wingrove v Wingrove (1885) 11 PD 81). Persuasion, appeals to affection, and even persistent requests can be legitimate. Adults are allowed to nag. The question is whether the testator remained free to choose.

Unlike lifetime gifts in equity, there is no presumption of undue influence in probate merely because the beneficiary was a carer, child, or solicitor (Parfitt v Lawless (1872) LR 2 P&D 462). The person alleging undue influence must prove it. Courts look at dependence, isolation, a sudden unexplained change, the beneficiary's role in the instructions, and whether the testator had independent advice (Re Edwards [2007] EWHC 1119 (Ch)).

Duress is coercion by threats (violence, abandonment, or similar pressure). Fraud covers deceit that induces the will, such as a false statement that a child has already been provided for. A forged signature is a different attack: the paper is not the testator's will at all.

Example. A daughter tells her isolated father, daily, that she will stop caring for him unless he leaves her the house. He is capable and he knows what the will says. If the court finds that his will was overborne, the will (or the gift) fails for undue influence. If he still chose freely, the same facts may look harsh but the will stands. Do not treat unhappiness among the excluded children as proof of coercion.

Formal requirements: Wills Act 1837, section 9

As substituted by the Administration of Justice Act 1982, section 9 provides that a will is not valid unless the following are met.

A formal attestation clause is not mandatory, but it raises the presumption of due execution (omnia praesumuntur rite esse acta). If there is no attestation clause, the probate registry will usually require affidavit evidence of due execution.

Witnesses must be able to witness a signature. A blind person cannot witness what they cannot see. A beneficiary, or the beneficiary's spouse or civil partner, who witnesses the will does not destroy the will, but section 15 voids the gift to that beneficiary (or to that spouse or civil partner). If the will is duly executed without counting that person's signature, the Wills Act 1968 can save the gift: three witnesses, one of whom is a residuary beneficiary, will often save the gift because two independent witnesses are enough for section 9.

The testator may sign earlier and later acknowledge that signature to two witnesses present together. The witnesses must be aware that the document is a will, or at least that they are being asked to witness a signature on a testamentary document; they need not know the contents.

Who has the burden of proof when challenging validity

FLK2 now lists this as its own bullet. SQE questions often turn on who must prove what, not on a vague sense that the will looks unfair.

Worked challenge. Fatima's 2024 will leaves her estate to her neighbour, who drove her to the solicitor and sat in the waiting room. Her children plead incapacity, want of knowledge and approval, and undue influence. Take the grounds in turn. The neighbour, as propounder, must prove Fatima had Banks v Goodfellow capacity. Due execution plus a rational will helps, but GP records of advanced dementia would shift the evidential burden back onto the neighbour. The neighbour's involvement is a suspicious circumstance, so the neighbour must also prove knowledge and approval (independent solicitor's notes of a private meeting would help). Undue influence is the children's allegation: they must prove coercion that overbore Fatima's will. Do not collapse all three grounds into "the neighbour was involved, so the will fails".

Exam traps. A large gift to a child who lived with the testator does not raise a probate presumption of undue influence. That is the lifetime-gift analysis. A will can fail for want of knowledge and approval even though Banks v Goodfellow is satisfied. Keep the grounds of challenge separate in any advice. Privileged wills are a narrow exception: do not use them to rescue a homemade civilian will with one witness.