It is estimated the orders in place against the private hospitals that have reported so far could lead to 140,000 fewer patients starting treatment by the end of March. But given some NHS hospitals are affected and not all the restrictions placed on private hospitals are thought to have been been declared that could be an underestimate.

David Hare, of the Independent Healthcare Providers Network, said: “Given it is patient choice driving demand for treatment in the independent sector – and the scale of the challenge in getting NHS waiting lists down – we‘ve been surprised by the extent of the proposed slowdown, which will leave significant amounts of available capacity going unused across both the independent sector and the NHS.”

Rachel Power, chief executive of the Patients Association, said: “These reports are deeply alarming and poses a serious risk to patients’ ability to access the treatment they urgently need.

“Calling it ‘activity management plans’ distracts from what this really is, another barrier standing between patients and timely care.

“It won’t just delay treatment – it will worsen conditions, reduce quality of life and lead to harm that could harm that could have been prevented.”

Sarah Walter, of the NHS Confederation, which represents regional health boards, said her members were having to make some “difficult decisions”.

“The NHS faces an unprecedented financial challenge which has resulted in system leaders having to make some very tough decisions over how limited funding and tight budgets should be spent.

“Leaders are caught between a rock and a hard place of being tasked with balancing their books and hitting the elective care target.”