Patient Autonomy CASES

September 30, 2025

National Case Law Archive

Lady justice with law books

Montgomery v Lanarkshire Health Board [2015] UKSC 11

A doctor failed to warn a diabetic mother about the risk of shoulder dystocia. The baby was born with severe disabilities. The Supreme Court ruled doctors must inform patients of all material risks of a treatment and any reasonable alternatives, establishing a patient-centred test for informed consent. Facts The appellant, Mrs Montgomery, was a woman of small stature and a type 1 diabetic. During her pregnancy, it was known that the baby of a diabetic mother is often larger than normal, which carries a 9-10% risk of shoulder dystocia during vaginal delivery (where the baby’s shoulders become stuck after the

September 16, 2025

National Case Law Archive

Lady justice with law books

Chester v Afshar [2004] UKHL 41 (14 October 2004)

A patient suffered paralysis from a small, undisclosed risk of spinal surgery. The surgeon's failure to warn breached his duty of care. The court found for the patient, modifying causation rules to vindicate her right to informed consent and make an informed choice. Facts The claimant, Miss Chester, suffered from long-standing lower back pain. She was referred to the defendant, Mr Afshar, an experienced neurosurgeon. Mr Afshar advised her to undergo elective spinal surgery. The procedure carried a small but unavoidable risk of serious neurological damage (cauda equina syndrome), estimated at 1-2%, even if performed with due care and skill.