The NHS is bracing itself for one of the toughest strikes in its history beginning on Thursday morning, England’s top doctor has warned.

Consultant doctors and hospital-based dentists will be taking strike action from 8am on Thursday until 8am on Saturday.

Professor Sir Stephen Powis, NHS national medical director, said that consultants will only provide staffing levels to cover emergency care, meaning the NHS will, in effect, experience two ‘Christmas Day service’ days in a row.

In contrast to strike action among other staff groups, no other clinicians can provide cover for consultants, so any planned care delivered by junior doctors or other healthcare professionals that requires even remote consultant supervision will need to be rescheduled. This means a significant amount of planned care involving junior doctors will be affected.

The action by consultants follows on from the longest period of industrial action in NHS history by junior doctors (five consecutive days), which started last Thursday and ended on Tuesday morning.

Data is yet to be published, but it is expected that the latest industrial action by junior doctors led to tens of thousands of appointments being postponed across five days, with an even bigger impact expected from the consultants’ strike.

The advice for the public who need care has not changed – people should use 999 in life-threatening emergencies and NHS 111 online for other health concerns. GP services and pharmacies are also available for patients and can be accessed in the normal way.

If you haven’t been contacted or informed that your planned appointment has been postponed, please attend as normal.

NHS national medical director Professor Sir Stephen Powis said: “This could undoubtedly be the most severe impact we have ever seen in the NHS as a result of industrial action, with routine care virtually at a standstill for 48 hours.

“Consultants will not only stop seeing patients themselves, but they won’t be around to provide supervision over the work of junior doctors, which impacts thousands of appointments for patients.

“It also follows on very closely from the longest ever junior doctors strike, which itself affected thousands of appointments, with back-to-back action leaving NHS services with almost no time to recover.

“We are working closely with the BMA and BDA to ensure that emergency and urgent care is prioritised and patients remain safe, but in the eighth month of industrial action, and with more than 600,000 appointments already affected, it’s becoming even more challenging to get services back on track after each round of action.”