10 Common Will Writing Mistakes UK (2026): How to Avoid Invalid or Ineffective Wills

Witnessing errors are one of the most common causes of will invalidity and contested estates: (1) THE WITNESSING REQUIREMENTS (WILLS ACT 1837 s.9): a valid will must be: (a) in writing; (b) signed by the testator (or by someone at their direction, in their presence); (c) signed by the testator in the presence of TWO witnesses present at the same time; (d) each witness must sign the will (or acknowledge their earlier signature) in the presence of the testator. All three — testator and both witnesses — must be present together at the moment of execution; (2) WITNESS IS A BENEFICIARY (WILLS ACT s.15): if a person who is a beneficiary under the will — or their spouse or civil partner — witnesses the will, the gift to that beneficiary is VOID. The will itself remains valid for other gifts, but the tainted beneficiary loses their legacy entirely. This rule applies even if the gift is a residuary gift — the residuary beneficiary gets nothing; (3) COMMON SCENARIOS: (a) a testator asks their adult child (who is a beneficiary) to witness as a convenience — the child loses their inheritance; (b) a testator's spouse witnesses, not realising they are a beneficiary under the will; (c) only one witness attends the signing — the will is invalid; (d) one witness signs later (not at the time of execution) — the will is invalid; (4) WHO CAN WITNESS: any adult of sound mind who is NOT a beneficiary (or beneficiary's spouse/civil partner). A stranger, a neighbour, a colleague — anyone who will receive nothing under the will; (5) CANNOT BE A WITNESS: a beneficiary; the spouse/civil partner of a beneficiary; a blind person (who cannot see the testator sign); a minor (under 18); (6) REMOTE WITNESSING: the Wills Act 1837 was temporarily amended to allow remote witnessing by video link for deaths between 31 January 2020 and 31 January 2022. This has now expired. A will must be witnessed by two persons physically present with the testator.

Marriage and divorce both have significant effects on a will, and many testators are unaware of the consequences: (1) MARRIAGE REVOKES A WILL (WA 1837 s.18): marriage (or the formation of a civil partnership) automatically revokes any will made before the marriage — unless the will was made in CONTEMPLATION of that specific marriage and is expressed to be made in such contemplation. The revocation is immediate and total. If the testator dies after marrying without making a new will, they die intestate — even if they had a perfectly valid will in place for years; (2) 'IN CONTEMPLATION OF MARRIAGE' EXCEPTION: a will is only preserved if it expressly states it is made 'in contemplation of my marriage to [name]'. If the will names the intended spouse but does not include this wording, the courts may still revoke it on marriage. Careful drafting is essential; (3) PRACTICAL CONSEQUENCE: a common scenario — a person makes a comprehensive will at age 40, leaving everything to their three children and naming trusted executors. At age 55 they remarry. The entire will is automatically revoked. Unless they make a new will promptly after the marriage, they die intestate. Under intestacy rules, the new spouse receives the statutory legacy (£322,000 as of 2024) and a share of the residue — the children from the previous marriage may receive far less than intended; (4) DIVORCE — REVOKES GIFTS TO EX-SPOUSE BUT NOT THE WILL (WA 1837 s.18A): divorce (or the dissolution of a civil partnership) does NOT revoke the will entirely. Instead, s.18A treats any gift to the former spouse (and any appointment as executor) as if the former spouse had died on the date of divorce. Everything else in the will remains valid; (5) WHAT DIVORCE DOES NOT DO: (a) it does not change who receives the residue if the former spouse was the residuary beneficiary and there is no alternative gift — the residue may pass on partial intestacy; (b) it does not remove the former spouse as trustee (only executor); (c) it does not affect rights under an LPA or letters of wishes; (6) BEST PRACTICE: review and update your will immediately on any change in marital status — marriage, civil partnership, divorce, or separation.

The residuary estate is everything the testator owned at death that is not specifically given away by name in the will. Failing to include a clear and effective residuary gift is one of the most damaging drafting mistakes: (1) WHAT THE RESIDUE IS: after all specific legacies, pecuniary legacies (cash gifts), and demonstrative legacies are paid, the residue is what remains. This includes: (a) property not specifically mentioned; (b) property bought after the will was made; (c) gifts that lapse (because the beneficiary predeceased); (d) proceeds of insurance, compensation, or other windfalls; (2) THE PARTIAL INTESTACY TRAP: if the will contains no residue clause — or the residue clause fails because the residuary beneficiary predeceased — then the residue passes under the intestacy rules (AEA 1925 s.46), not under the will. This is partial intestacy; (3) COMMON SCENARIOS: (a) the testator gives away specific items (house to spouse; jewellery to daughter; car to son) but forgets to add 'and the remainder of my estate to [person]' — everything else falls into intestacy; (b) the residue is left to one person who predeceases, and there is no substitution clause or alternative beneficiary — partial intestacy again; (4) LAPSE — WHEN SPECIFIC GIFTS ALSO FAIL: under the common law, if a beneficiary predeceases the testator, the gift LAPSES — it falls back into residue. If the residue is also failing, the lapsed specific gift falls into intestacy. Exception: s.33 Wills Act 1837 (anti-lapse for testator's own children or issue); (5) THE SOLUTION: every will should include: (a) a clear residuary gift ('I give the remainder of my estate to...'); (b) substitution clauses for each named beneficiary; (c) a longstop residuary beneficiary (e.g. a charity) in case all primary beneficiaries predecease; (6) READING THE WILL CAREFULLY: the residue clause should be read alongside all specific gifts to ensure nothing falls into the gap. A well-drafted will from WillSafe UK includes these provisions as standard.

Executor and trustee mistakes can make an otherwise valid will extremely difficult to administer: (1) NO SUBSTITUTE EXECUTOR: if a sole executor dies before or with the testator, and there is no substitute named, the will has no named executor. The next of kin must apply for letters of administration with will annexed — a more complex and time-consuming process. For a will appointing a professional executor who has since retired, or a friend who has predeceased, the same problem arises; (2) TOO FEW EXECUTORS FOR TRUSTS: if the will creates a trust (e.g. a trust for minor children) at least TWO trustees are required for land held on trust (LPA 1925 s.27). Appointing a single executor who also acts as sole trustee creates a legal obstacle when dealing with trust property; (3) NOT REMOVING AN EX-SPOUSE AS EXECUTOR: while divorce revokes the ex-spouse's appointment as executor (WA s.18A), separation does not. If the testator separated but did not divorce, the separated spouse may still be the named executor — with full access to and control over the estate; (4) EXECUTOR WHO CANNOT ACT: naming a professional executor who has since moved firms, retired, or died; naming a minor (executors must be 18+ to prove the will); naming someone living abroad (practical difficulties though not legally invalid); (5) NO GUARDIANS FOR MINOR CHILDREN: a common oversight for parents. Without a guardian appointment, the surviving parent automatically takes custody. But if both parents die together (commorientes; or in separate accidents), the court decides who cares for the children — potentially family members who are unknown to the children or the wrong choice; (6) DISCRETIONARY TRUST WITHOUT PROPER TERMS: a will that says 'I give my estate to my trustees on trust for my children at their discretion' without specifying the age of distribution, trustee powers, maintenance provisions, and accumulation periods creates administrative uncertainty. If the trust is created, trustees need full TA 2000 powers and proper charging clauses.

Tax and asset planning errors are the most expensive mistakes — they can cost tens of thousands of pounds in avoidable inheritance tax: (1) RELYING ENTIRELY ON THE SPOUSE EXEMPTION WITHOUT CONSIDERING THE RNRB: many people simply leave everything to their spouse and assume the IHT will be sorted on the second death. This works for the NRB (TNRB) but the RNRB creates a new trap: if everything goes to the spouse on first death, the RNRB is preserved via TRNRB (£175,000 transferable). But if the second spouse's estate includes a house that passes to a direct descendant, the combined RNRB can reach £350,000. Understanding this and planning correctly can save up to £140,000 in IHT; (2) ASSETS THAT PASS OUTSIDE THE WILL: testators frequently try to include assets in their will that do not pass by will at all: (a) jointly tenanted property (land, savings accounts) — passes automatically to the surviving joint owner by right of survivorship; the will has no effect on this; (b) pension death benefits — do NOT form part of the estate and cannot be directed by will; beneficiary nomination with the pension scheme is separate and essential; (c) life insurance in trust — passes to the trust beneficiaries directly, not through the estate. Testators should understand what IS and what IS NOT in their estate; (3) NOT DEALING WITH THE FAMILY HOME IN JOINT TENANCY: if the family home is owned as joint tenants, it CANNOT be left by will. On the first death, the share passes automatically to the survivor. If the intention is to use a nil-rate band trust, a deed of severance is needed first to convert the joint tenancy to a tenancy in common; (4) OUTDATED WILL AFTER MAJOR ASSET CHANGES: a will leaving 'my house at [address]' to a beneficiary is invalidated by ademption if the house is sold. A will leaving specific shareholdings is similarly affected if the shares change form. Keep wills updated to reflect current asset descriptions; (5) FAILING TO TAKE IHT ADVICE: for estates worth more than £325,000 (or £500,000 for a property-owning couple with a direct descendant), professional IHT advice alongside the will can identify: (a) gifts to reduce the estate; (b) business or agricultural property relief; (c) charitable legacies for the 36% rate; (d) life insurance in trust to fund IHT.