Mental Capacity: Making a Will vs Making a Lasting Power of Attorney
When it comes to planning ahead, one of the most common concerns people have—especially when age or illness starts to take its toll—is whether they or their loved ones still have the mental capacity to make key legal decisions.
Two of the most important documents we deal with in estate planning—the Will and the Lasting Power of Attorney (LPA)—each have their own legal tests for capacity. They’re similar in many ways, but there are some crucial differences worth knowing.
Here’s a breakdown in plain English.
What Is ‘Mental Capacity’?
In short, it’s your ability to understand the decision you’re making, retain the relevant information, weigh it up, and communicate your wishes.
Both Wills and LPAs require the person making them to have capacity at the time of signing—but what that looks like can differ depending on the document.
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Capacity to Make a Will (the ‘Banks v Goodfellow’ test)
The legal test for Wills is based on a Victorian court case from 1870—and it still stands today.
To make a valid Will, you must:
- Understand what a Will is and what it does.
- Know (in broad terms) what you own.
- Be aware of who might reasonably expect to benefit (spouse, children, etc.).
- Be free from any mental disorder that affects your decision-making.
That doesn’t mean you need to remember your exact bank balance, or list every item in your house. It means you need to grasp the general picture and make a rational choice, free from pressure or confusion.
If someone’s memory is fading, or they’ve had a diagnosis of dementia, it doesn’t necessarily mean they lack capacity to make a Will. In fact, many people still do have sufficient capacity if the Will is simple and well-explained.
Capacity to Make a Lasting Power of Attorney (Mental Capacity Act 2005)
For LPAs, we apply the Mental Capacity Act. The standard here is slightly different and sometimes stricter, especially if the LPA covers complex decisions or family dynamics.
To make an LPA, the person must:
- Understand what an LPA is and what it authorises.
- Understand the scope of the authority being given (e.g. finances, health decisions).
- Be able to weigh up who to appoint and why.
- Recognise the risks of abuse or mismanagement.
- and remember that at least for the time taken to take instructions and again on signature.
Here’s where it gets tricky: someone might have just enough capacity to make a Will, but not enough to set up an LPA—especially if their understanding of legal authority and future implications is muddled.
That’s why the law requires an independent certificate provider (like me!) to confirm capacity for every LPA. It’s a safeguard to make sure the person knows what they’re signing and isn’t being pressured.
Key Differences at a Glance
| Will | LPA | |
|---|---|---|
| Legal test | Banks v Goodfellow (1870) | Mental Capacity Act 2005 |
| Assessed by | The person taking instructions (you/me) | Certificate provider (e.g. professional like me) |
| Understanding needed | Nature of a Will, property, beneficiaries | Nature of LPA, scope, attorneys’ role |
| Timeframe of effect | Comes into effect after death | Comes into effect while still alive timing to be agreed. |
| Complexity of understanding | Usually simpler | Often more complex (e.g. health vs finances) |
| Pressure/safeguards | More vulnerable to undue influence | Built-in certificate and registration steps |
What If Someone’s Capacity Is Borderline?
Sometimes it’s not clear-cut. They may have good days and bad days, or become confused under stress.
In those cases, I often work with the family to:
- Arrange meetings at the best time of day (mornings tend to be better).
- Use simple language and avoid jargon.
- Document everything carefully.
- Bring in a medical opinion if needed (a GP letter or specialist assessment).
Final Thought: Planning Early Is Kindness in Action
It’s far easier to make a Will or LPA when capacity is not in question. Sadly, many people wait too long—especially for LPAs—and then the family has to apply to the Court of Protection, which is costly and slow.
If you’re reading this for yourself or someone you care about, don’t leave it too late. If in doubt, just ask. I’m happy to give an honest opinion, with no obligation.
NB The law is currently under consideration, and it is unlikely it will be made easier, so always safer to get started.
To make a Will or LPA or review one, contact:
Stephen Pett CmpnSWW, AffSTEP, DMS
steve@theprofessionalwillwriter.co.uk
01323 766766
5 Malcolm Gardens, Polegate, BN26 6PN