When to use NHS consent form 4 for best-interests decisions
Form 4 applies to adults aged 16 and over who cannot make this particular decision at this particular time. Capacity is never assumed to be absent because of a diagnosis, age or behaviour.
- Advanced dementia where the treatment decision cannot be understood or retained
- Unconsciousness or delirium at the time treatment is needed
- Severe learning disability affecting this specific decision
- Acute brain injury or the effects of a stroke
For children who cannot consent, a parent signs NHS consent form 2 rather than a best-interests record.
The two-stage capacity test under the Mental Capacity Act 2005
The Act sets out a functional test that must be recorded on the form. Every practicable step to support the patient's own decision must be tried first.
- Stage one — is there an impairment of, or disturbance in, the functioning of the mind or brain?
- Stage two — does that impairment mean the patient cannot understand, retain, weigh or communicate this decision?
Write down how the assessment was carried out. A conclusion with no working shown is the weakest part of most completed form 4 records.
Making a best-interests decision, not a substituted one
Best interests is not the clinician's view of the best outcome. It is a structured attempt to reach the decision this patient would most likely have wanted.
Consider their past and present wishes, their beliefs and values, and anything they wrote down while they had capacity. Choose the option least restrictive of their rights and freedoms.
Who must be consulted before treatment proceeds
Consultation is a legal duty, not a courtesy. Record who was spoken to and what they said, even where their views did not change the outcome.
- Anyone named by the patient as someone to be consulted
- Carers, family members and close friends interested in their welfare
- A registered health and welfare attorney or a court-appointed deputy
- An Independent Mental Capacity Advocate where the patient is unbefriended and the treatment is serious
Family members cannot consent on the patient's behalf. They inform the decision; the responsible clinician makes it and signs the form.
Advance decisions and attorneys that override the form
A valid and applicable advance decision to refuse treatment is legally binding. If one exists and covers this treatment, it must be followed and form 4 is not the route to treat.
A registered health and welfare Lasting Power of Attorney gives the attorney authority to consent or refuse on the patient's behalf. In that case the attorney signs a normal consent form rather than a best-interests record.
How other tier-1 countries handle incapacity
Every tier-1 system has a substitute decision-making route, but the mechanism and terminology differ substantially.
United Kingdom
England and Wales apply the Mental Capacity Act 2005 with form 4; Scotland uses the Adults with Incapacity Act 2000 and its section 47 certificate.
United States
A healthcare proxy or state surrogate hierarchy usually decides, often applying a substituted-judgment standard rather than best interests — see our general medical consent form.
Canada, Australia and New Zealand
Canadian provinces use substitute decision-maker legislation, Australian states appoint guardians through tribunals, and New Zealand relies on enduring powers of attorney under the PPPR Act.