Valid consent (capacity, informed, voluntary)
What it means
For consent to be valid the person must have CAPACITY, be adequately INFORMED, and give it VOLUNTARILY (free from coercion). Consent can be express or implied and must be specific to the procedure. The amount of information required is set by Montgomery (material risks). Lack of any element invalidates consent — treating without valid consent can be battery.
Worked example
A patient signs a form but was not told about a common, significant complication — consent is not valid (not adequately informed) and the threshold is what THIS patient would want to know.
In the exam
A patient consents to surgery but was never warned of a material risk that a reasonable person in her position would want to know about.
What settles it
The standard for HOW MUCH to disclose is now patient-centred (Montgomery: material risks), not what a body of doctors would disclose (the old Bolam test).
Classically confused with
Montgomery & material risk
Source: GMC consent guidance