The strike will have a major impact on the National Health Service (NHS) which employs more than 50000 junior doctors graduates with years of experience who have not yet completed their professional qualifications.

While there have been several recent walk-outs this one will affect hospital emergency care such as accident and emergency (A&E) and maternity units for the first time although senior doctors and nurses will still be on duty.

Nearly 13000 operations and 113000 appointments have been postponed around the period of the strike which runs from 8.00am to 5.00pm (0700 GMT to 1600 GMT) on Tuesday and Wednesday.

'Anything unprecedented like this places a significant pressure on the NHS' Anne Rainsberry national incident director for NHS England told BBC radio.

The British Medical Association (BMA) the doctors' trade union has not ruled out a permanent strike or mass resignations as a way of trying to force the government's hand over the new staff contract on offer.

A key sticking point has been on how much financial compensation junior doctors should get for working on Saturdays.

But Health Secretary Jeremy Hunt said the new contract was a 'very fair deal' that rewarded junior doctors better than paramedics police officers and fire officers for working unsociable weekend hours.