“Mental capacity” is not one single test. The law asks a different question depending on whether you are making a Will, or making a Lasting Power of Attorney.
| Wills | Case law — Banks v Goodfellow (1870). Asks whether you understood the specific act of making this Will. |
| Lasting Powers of Attorney | Statute — the Mental Capacity Act 2005. Asks whether you can understand, retain, use and communicate a decision, at the time it needs to be made. |
The test for testamentary capacity comes from Banks v Goodfellow (1870). The testator must understand:
See also Making a Will.
For an LPA, the test is set out in the Mental Capacity Act 2005 (“MCA”).
Section 2 — people who lack capacity. A person lacks capacity in relation to a matter if, at the material time, they are unable to make a decision for themselves because of an impairment of, or a disturbance in the functioning of, the mind or brain. It does not matter whether that impairment or disturbance is permanent or temporary. A lack of capacity cannot be established merely by reference to a person’s age or appearance, or a condition or aspect of behaviour which might lead others to make unjustified assumptions about their capacity.
Section 3 — inability to make decisions. A person is unable to make a decision for themselves if they cannot: understand the information relevant to the decision; retain that information; use or weigh that information as part of the process of making the decision; or communicate their decision, whether by talking, sign language, or any other means.
A person is not to be regarded as unable to understand relevant information if they can understand an explanation given in a way appropriate to their circumstances — using simple language, visual aids, or any other means. Being able to retain the information for a short period only does not, on its own, prevent them being regarded as able to make the decision. The relevant information includes the reasonably foreseeable consequences of deciding one way or another, or of failing to decide at all.
In both cases, capacity must be assessed at the time the document is made or the decision is taken — and, for an LPA, this must be certified by an independent person. See also Powers of Attorney.