Junior doctors are to carry out the first full walkout of doctors in the history of the NHS as a result of the ongoing dispute with the Government over new working conditions.
In the second of two strike actions planned for April, junior doctors - everyone up to consultant level - will do a full walkout, the British Medical Association (BMA) said.
In previous days of industrial action doctors have still provided emergency cover.
The BMA said the move follows the "continued refusal by the Government to step back from its decision to impose a new contract on junior doctors from August this year and resolve the dispute by re-entering talks".
The Department of Health said the move was "desperate and irresponsible" and said a full walkout would "inevitably put patients in harm's way".
The doctors' union has two sets of action planned. A 48 hour strike action starting on Wednesday April 6 at 8am, where junior doctors provide "emergency care only", will go ahead as scheduled, the BMA said.
But the industrial action set for April 26 and April 27 will now be a "full withdrawal of labour" by junior doctors between the hours of 8am and 5pm on the two days.
Dr Johann Malawana, chairman of the BMA's junior doctor committee, said: "No junior doctor wants to take this action but the Government has left us with no choice. In refusing to lift imposition and listen to junior doctors' outstanding concerns, the Government will bear direct responsibility for the first full walkout of doctors in this country.
"The Government is refusing to get back around the table and is ploughing ahead with plans to impose a contract junior doctors have no confidence in and have roundly rejected.
"We want to end this dispute through talks but the Government is making this impossible, it is flatly refusing to engage with junior doctors, has done nothing to halt industrial action and is wilfully ignoring the mounting chorus of concerns over its plans...from doctors, patients and senior NHS managers. Faced with this reality what else can junior doctors do?
"We deeply regret the disruption to patients and our message to patients is clear; this action is wholly avoidable but the Government must choose talks over imposition.
"The rest of the UK has taken a different, constructive path on junior doctors' contracts with only the Health Secretary in England choosing imposition over talks.
"The fact that tens of thousands of junior doctors have taken industrial action and 98% of those who voted to support action, including a full withdrawal of labour, demonstrates the continued strength of feeling amongst junior doctors about this politically driven imposition.
"Junior doctors are committed to ensuring the best possible care for their patients and already work seven days a week, around the clock under the existing contract. In focusing on junior doctors, the Government is seeking, yet again, to gloss over the fact that the biggest barrier to a seven-day NHS is not doctors' contracts, but a chronic lack of investment and a shortage of staff.
"For the sake of patients, doctors and the future of the NHS the Government must put politics to one side, get back around the table and end this dispute through talks."
A Department of Health spokeswoman said: "This escalation of industrial action by the BMA is both desperate and irresponsible – and will inevitably put patients in harm's way.
"If the BMA had agreed to negotiate on Saturday pay, as they promised to do through Acas in November, we'd have a negotiated agreement by now.
"Instead, we had no choice but to proceed with proposals recommended and supported by NHS leaders."
The major sticking point has been over weekend pay and whether Saturdays should attract extra "unsocial" payments.
Currently, 7pm to 7am Monday to Friday and the whole of Saturday and Sunday attract a premium rate of pay for junior doctors.
The Government wanted the Saturday day shift to be paid at a normal rate in return for a hike in basic pay.
The BMA rejected this and urged Mr Hunt to reduce the offer of basic pay and instead have better premium rates on Saturdays.
The imposed contract, which is due to come into force in August, has an increase in basic salary of 13.5%.
Under the new arrangements, Mr Hunt said no doctor working contracted hours would see a pay cut, while night shifts and long shifts would be limited.
But 7am to 5pm on Saturdays will be regarded as a normal working day.