Hospitals are braced for two day of strikes by junior doctors in a dispute with the government over contracts.
Medics will walk out between 8am and 5pm on Tuesday and Wednesday after health secretary Jeremy Hunt imposed a new contract on junior doctors without a negotiated settlement being reached.
All junior doctors, including those who would have been on call to provide emergency cover, will be called out on strike in an unprecedented move by the British Medical Association (BMA).
Operations will be cancelled and people are being urged only to go to A&E if they are in a genuine emergency - but NHS bosses said contingency plans would be in place.
Dr Sarah Robertshaw, head of emergency medicine at Mid Yorkshire Hospitals Trust, said: “We know people are worried about what will happen if they become ill during the junior doctor strike.
“We already have robust contingency and resilience plans in place for the two days of the strike.
“Our focus is to ensure we can provide a safe service for patients and that anyone who needs help in an emergency can get it.
“Over the strike period the Emergency Departments will be open but they need to be able to concentrate their efforts in managing critically ill and injured patients.”
People who have planned hospital procedures on the strike days will be contacted if their appointments need to be re-arranged, but they are advised to check the hospital website if they have not heard anything.