Living Wills / Advanced Decision
If you lose mental capacity in the future, a Living Will enables you to make a binding Advanced Decision to refuse life-sustaining treatment, and also setting out which treatments you would or would not wish to receive.
To make an Advance Decision you have to be 18 or over and have the mental capacity to make it.
You need to specify the treatment to be refused and the circumstances in which your refusal would apply. You must state that the decision stands even if your life is at risk. You must not have been under the influence of another person when making the decision.
It must be in writing and signed and witnessed (or signed by someone else on your behalf if you are not able to sign).
Your advanced statement could mention someone you would like to be consulted about your treatment when a decision needs to be made.