A patient of head injury, has no relatives and requires urgent cranial decompression, doctor should:
Operate without formal consent is necessary in this case, delay will lead to death of the patient. Ref: Parikh's Textbook of Medical Jurisprudence Forensic Medicine and Toxicology, 5th Edition, Page 569 and 6th Edition, Page 1.37
Operate without formal consent
Take police consent
Wait for relatives to take consent
Take magistrate consent