Contesting a Will: Grounds, Costs and What the Law Actually Allows

Contesting a will is more legally constrained than popular perception suggests - you generally can’t challenge a will simply because you think it’s unfair, but there are specific, recognised grounds the law does allow, and one route in particular that’s broader than most people realise. That’s quite different from a Deed of Variation, which lets beneficiaries voluntarily agree to redirect an inheritance without any dispute or court process at all.

The key distinction: challenging validity vs claiming inadequate provision

There are two fundamentally different types of claim, often confused with each other: challenging whether the will itself is legally valid, and claiming you should have received more from an estate even if the will is valid (under the Inheritance (Provision for Family and Dependants) Act 1975). These have different grounds, different eligible claimants, and different processes.

Grounds for challenging a will’s validity

• Lack of testamentary capacity - the person didn’t understand what they were doing, the extent of their estate, or who might reasonably expect to benefit, at the time the will was made. (The Law Commission’s 2025 draft Wills Bill proposes replacing this test with the Mental Capacity Act 2005 test, but as of October 2026 the government hasn’t yet taken that forward.)
• Lack of due execution - the will wasn’t properly signed and witnessed according to legal requirements (in England and Wales, this generally means signed in the presence of two witnesses, both present at the same time).
• Undue influence - someone pressured or coerced the person into making a will that didn’t reflect their genuine wishes. This is generally difficult to prove, since it requires evidence of actual coercion, not just that someone had influence or that the will favours one person over others.
• Fraud or forgery - the will, or a signature on it, was fraudulent.
• Lack of knowledge and approval - the person didn’t actually know and approve of the will’s contents, which can overlap with capacity or undue influence claims in practice.

The broader route: the Inheritance (Provision for Family and Dependants) Act 1975

This Act allows certain categories of people to claim for ‘reasonable financial provision’ from an estate, even if the will is entirely valid - this is a genuinely different and often more accessible route than challenging validity, since it doesn’t require proving something went wrong with the will itself, only that the provision made (or not made) for the claimant isn’t reasonable.

• Who can claim: a spouse or civil partner, a former spouse or civil partner who hasn’t remarried or formed a new civil partnership, a child (including adult children in some circumstances), someone treated as a child of the family, a cohabiting partner who lived with the deceased for the whole two years immediately before the death, or anyone who was financially dependent on the deceased.
• The time limit: claims generally must be made within 6 months of the Grant of Probate or Letters of Administration being issued (the court can allow a late claim, but permission isn’t guaranteed) - a genuinely tight window, and a key reason anyone considering a claim should seek advice promptly rather than waiting.
• What the court considers: the size of the estate, the claimant’s financial needs and resources, the deceased’s reasons for the will as they made it, and the needs of other beneficiaries, among other factors - courts have considerable discretion in what constitutes ‘reasonable’ provision.

The realistic cost and process

Contesting a will, through either route, can be genuinely expensive - often running into many thousands of pounds in legal fees, particularly if the case proceeds to a full court hearing rather than settling. Many disputes are resolved through mediation or negotiation before reaching court, which is generally faster and less costly than a full trial, and solicitors experienced in this area will typically discuss the realistic costs and chances of success before proceeding.

Why acting quickly matters

Beyond the strict 6-month time limit for 1975 Act claims, delaying any kind of will dispute risks the estate being distributed in the meantime - while it’s sometimes possible to recover assets from beneficiaries after distribution, this adds considerable complexity, cost, and uncertainty compared with raising concerns before the Grant of Probate is issued or shortly afterward.

What to do if you’re considering a claim

• Seek specialist advice promptly, given the tight time limits involved, particularly for a 1975 Act claim.
• Consider whether mediation might resolve the dispute without full litigation, which is often faster, less costly, and less damaging to family relationships.
• Be realistic about costs versus the value of the potential claim - legal fees can consume a significant portion of a modest disputed sum, making the financial case for proceeding worth weighing carefully.

The bottom line

Contesting a will isn’t possible simply on the grounds of feeling the outcome is unfair - but genuine grounds exist for challenging a will’s validity, and a broader, often more accessible route exists under the Inheritance (Provision for Family and Dependants) Act 1975 for certain categories of claimant, subject to a strict 6-month time limit. Prompt, specialist advice is essential given both the time constraints and the genuine cost involved.