Re T (Adult: Refusal of Medical Treatment) 
A pregnant Jehovah's Witness in road traffic accident, she refused blood transfusion according to her own religious belief.
Judgment by Lord Donaldson MR: Doctors faced with a refusal of consent have to give very careful and detailed consideration to the patient's capacity to decide at the time when the decision was made. The more serious the decision, the greater the capacity required. If the patient had the requisite capacity, they are bound by his/her decision. If not, they are free to treat him/her in what they believe to be his/her best interests.