What is the Banks v Goodfellow test for capacity in BC wills?

This answer covers the law of British Columbia.

The Banks v Goodfellow test is the case-law standard that British Columbia courts use to decide whether a will-maker was mentally capable when making a will. The Wills, Estates and Succession Act (WESA), section 36, requires that a will-maker be mentally capable but does not define the test, so the courts apply the case law together with the section. Banks v Goodfellow, decided in 1870, is described as the leading authority on testamentary capacity and is still applied about 150 years later.

Age is a separate question from capacity. A person who is 16 or older and mentally capable may make a will, and a will made by someone under 16 is not valid. The test also reaches insane delusions: in 1936 the Supreme Court of Canada applied it to delusions about a will-maker's wife that affected the gifts in the will.

Whether a particular person had capacity depends on the facts, and the detailed parts of the test and how a court weighs medical and witness evidence are worth confirming with a lawyer. Where suspicious circumstances relate to capacity, the person relying on the will carries the legal burden of proving it, and the standard remains the balance of probabilities.