Hospital chiefs have said they cannot guarantee patient safety as junior doctors today begin four-day strike action this week.

Junior doctors, who make up 40% of the medical workforce, are calling for a 35% pay rise arguing their salaries have been cut by 25% in real terms in the salaries since 2008/09.

NHS bosses say the strike action is set to be the most disruptive yet with the British Medical Association refusing to exempt any services from being impacted by the dispute, although it has said doctors will provide support in the event of lives being at immediate risk.

One hospital trust chief executive said: “This is less about what planned routine work gets pulled down, and everything about maintenance of safety in emergency departments, acute medicine and surgery”. He added: “Concerned doesn’t begin to describe it.”

Another said: “I am not confident this time that we can maintain patient safety as we will not be able to provide the cover.”

The chief executive of NHS Providers, Sir Julian Hartley, said: “It’s clear from our extensive dialogue with trust leaders that we are in uncharted territory.

“Yet again we are seeing colleagues pull out all the stops to minimise disruption and ensure patient safety.

“But the challenges here are unprecedented.

“It’s particularly important during the strike that in the event of an emergency the public continue to turn to the NHS. No effort will be spared to provide the care they need.

“But for less urgent cases, people should look first to 111 online if they can, to access appropriate treatment and advice.

“Even now it’s not too late for the two sides in this dispute, the government and the unions, to recognise the gravity of the situation and step back from the brink.

“We need a solution to prevent further strikes, and we need it now.”