Jeremy Hunt has signalled the Government could be prepared to back down on plans to impose all-day Saturday working hours on junior doctors as he sought to calm fears that the new contracts would cut pay and lead to longer hours.

In a move that he hopes will head off potentially crippling NHS strikes, the Health Secretary wrote a letter to the British Medical Association (BMA) saying reports that salaries will be cut by 30 per cent were wrong and said he was “saddened by the distress” this had caused.

Under the Government’s plans, junior doctors’ normal hours of work will be extended from the current working hours of 7am-7pm Monday to Friday to 7am-10pm Monday to Saturday.

This move has angered medics, who argue they will lose out financially because evenings and Saturdays will be paid at the standard rate rather than the higher rate for extra hours.

But in the letter Mr Hunt has given “absolute guarantees” on pay and working hours, insisting junior doctors would still be able to benefit from four or five progression pay rises during their training and promising that the new deal will not require doctors to work more than 48 hours a week.

In his letter to Dr Johann Malawana, chair of the BMA junior doctors committee, Mr Hunt wrote: “I can give an assurance that nights and Sundays will continue to attract unsocial hours payments. I would be pleased to discuss in negotiations how far plain time working extends on Saturdays."

He told the BMA that the Government was "not seeking to save any money” from the changes. Instead they are designed to help deliver the Government’s pledge to open the NHS to seven-day working and improve patient safety, he said.

Mr Hunt wrote: “Firstly, this is not a cost-cutting exercise. I can give you a categorical assurance that I am not seeking to save any money from the junior doctors’ paybill.

“Whilst I want to see an end to automatic annual increments [with pay rises instead based on moving through the stages of training and taking on more responsibility], these changes would be cost-neutral, rather than cost-saving.

“This will mean that junior doctors would still benefit from four or five progression pay rises as they move through training.”

He added: “In any scenario, I can give an absolute guarantee that average pay for juniors will not reduce. I have already given my assurances that GP trainees will not be disadvantaged compared with the current system.

In an interview with The Independent last week Mr Hunt said he would work to ensure no junior doctors lost money as a result of the new contracts, a concession designed to head off a walkout by England’s 53,000 juniors that could cripple NHS services.

The new junior doctor contracts are part of the Government’s pledge to open up the NHS to seven-day working, a move designed to stop the disproportionately high death rates suffered in the health service at weekends.