Doctors and supporters have been marching through Truro to toots of support from drivers passing by, while picket lines have been outside Plymouth’s Derriford Hospital.
It is the first time junior doctors have walked out of routine and emergency care, and the first all-out strike in NHS history.
Services such as accident and emergency, maternity and intensive care have all been affected, with emergency cover provided by consultants and senior medical staff alongside nurses and paramedics.
The industrial action started at 8am and will continue until 5pm. Further action is planned tomorrow between the same hours.
The dispute centres on a seven-day-a-week contract for junior doctors, which health secretary Jeremy Hunt now plans to impose.