Lemon juice & your Will: why DIY fails

Last verified: 18 September 2025 (England & Wales)

Quick-read summary

In the 1990s, a man famously tried to rob a bank after rubbing lemon juice on his face, convinced it would make him invisible to CCTV. It didn’t. The story has since been used to illustrate the Dunning–Kruger effect, which occurs when people who lack expertise overestimate their competence.

The same trap turns up in Wills and Lasting Powers of Attorney (LPAs). People write documents themselves, or rely on a friend or relative who “did theirs,” and assume everything’s fine. But you can’t truly test a Will until you die, and you can’t thoroughly test an LPA until you lack capacity — by which time it’s too late to fix problems. The practical, safe alternative is a professional review — our Wills MOT or LPA Servicing — before anyone ever needs to rely on the document.

After all, you don’t want everything you are (your LPAs) and everything you own (your Will) to rely on a document that turns out to be a lemon.

Practical checklist — read this first

If any of the following apply, it’s time for a professional Wills MOT or LPA Servicing:

You or a family member wrote the Will or LPA with no legal review.
You used a cheap online template or shop packet.
Witnessing, signing, or capacity is uncertain.
You copied clauses from someone else’s Will.
You haven’t updated your Will/LPA since family, property or health circumstances changed.
You’re assuming “my sister did it and it’s fine” or “my friend witnessed it” is enough.

What to consider

The lemon-juice problem

The robber thought lemon juice made him invisible to CCTV. On paper, it sounded plausible, but reality was different. DIY legal documents can be the same: they look fine, but don’t stand up when tested in court or registration.

You can’t reliably self-test — but you can have it tested

You can’t “try out” a Will by living longer, and you can’t simulate incapacity to test an LPA. The sensible step is a Wills MOT or LPA Servicing — a professional check-up that tells you if your documents will work and why.

Where DIY commonly fails

Witnesses not signing correctly.
Beneficiaries accidentally disinherited if they die before you.
LPAs rejected at registration due to errors in the certificate provider or signing process.
Property ownership does not match what the Will tries to do.

Cases

The “helpful” sibling
Mrs A asked her brother to help with her Will because “he did ours.” It looked fine — until the family discovered the property was owned jointly in a way the Will couldn’t change—result: months of delay and legal costs. A Wills MOT would have spotted it immediately.

Case 2 — The LPA that stalled
Mr B’s DIY LPA was rejected because sections weren’t appropriately signed. The family were powerless for weeks. An LPA Servicing check would have prevented that at minimal cost.

FAQs

Q: I used an online Will template — is that going to be fine?
A: It depends. If you’re single, renting, and have no children, a basic Will may suffice. But most people have more going on:

Married or in a partnership
Own a home
Have children or stepchildren
Want different outcomes if beneficiaries die in a particular order

An online Will cannot cover all these scenarios. A thorough fact-find with a professional takes at least an hour. If you wrote yours in 15 minutes, something’s already missing.

Q: My sister says she “tested” hers and it was fine — why isn’t that enough?
A: Because unless her Will has actually gone through probate, she hasn’t tested anything. The “acid test” happens only when the document is needed. A Wills MOT gives you a real pre-test while you’re still here to correct it.

Q: Can a Will be fixed after it’s signed?
A: Sometimes, but often it’s cleaner and safer to start again. Codicils or patched-up documents create confusion.

Q: How about LPAs? Can they be corrected later if there are mistakes?
A: Registration delays are common with DIY LPAs, and some are refused outright. Our LPA Servicing makes sure your document is registered and ready before it’s needed.

Q: What are the most common mistakes with LPAs?
A: We’ve listed them here: 50 most common mistakes with LPAs. They show how easy it is to get things wrong, even with the best intentions.

Optional technical notes (for those who want the detail…)

Witnessing: For a Will to be valid in England & Wales, the testator must sign (or acknowledge) in the presence of two witnesses who also sign in the testator’s presence. Witnesses cannot be beneficiaries (or their spouses).
LPAs: Must be correctly signed in sequence and registered with the Office of the Public Guardian. Any gap can cause rejection.
Joint property: The way a property is owned (joint tenants vs tenants in common) can overrule a Will if misunderstood.

Sources & further reading

gov.uk — Make, register or end a Lasting Power of Attorney
legislation.gov.uk — Wills Act 1837
Verywell Mind — Overview of the Dunning–Kruger effect

Next steps

Already have a Will? Book a Wills MOT — a professional review to make sure it works when needed.
Already have an LPA? Ask about LPA Servicing — we’ll check registration and validity.
No documents yet? Let’s draft them correctly from the start.

Don’t risk your family’s future on a document that looks fine but later turns out to be a lemon.

What does lemon juice have to do with your Will?