NHS funding levels should be checked by the government’s budget watchdog amid public distrust of the figures and a worsening winter crisis in hospitals, John McDonnell has said.

The shadow chancellor wrote to Robert Chote, head of the Office for Budget Responsibility (OBR), asking him to look at NHS funding levels, as doctors warned that the shortage of resources in health and social care has created a crisis.

There have been a number of calls from Labour and the Liberal Democrats for an independent auditor for the NHS. But McDonnell called on the existing OBR to see if it could establish the truth about public spending on the NHS.

The level of NHS funding has become hotly contested amid claims that cuts to social care have been causing unprecedented pressure on hospitals and further controversy over the government’s claims to be putting in another £10bn a year into the health service by the end of this parliament.

“It has become clear that Labour’s warnings of a looming winter crisis in the NHS were not heeded,” McDonnell wrote to Chote. “And we have seen in recent days that the British Red Cross has now had to describe the ongoing situation as a humanitarian crisis. The response from the prime minister at the weekend was to play down this situation despite the volume of continued complaints from frontline NHS staff.”I strongly believe that this is leading to widespread public distrust in the government’s presentation of the level of funding and support for the NHS and social care. Therefore, it seems that now is the time to assess further enhancing the role of the OBR, and add additional responsibilities to your organisation.”

He suggested there should be an “annual standalone report that assesses short-medium term policy decisions made on health spending by the government, that takes into account the analysis you already do on the long-term trends and drivers of health spending.”

On Monday night, frontline doctors issued an unprecedented warning that patient safety was at risk at many A&E units across the NHS because hospitals are overwhelmed.

The health secretary, Jeremy Hunt, told the Commons in an emergency statement that hospitals may have to cancel operations and outpatient appointments so that staff can concentrate on the sickest patients.

GPs may also be drafted in to help hospitals cope with record demand for medical care. He also provoked controversy by suggesting the four-hour treatment target should exclude people who waste time by presenting with minor ailments.

The Royal College of Emergency Medicine said a substantial number of A&E departments were falling significantly short of the four-hour standard -; but Hunt said that as many as 30% of those turning up were neither an urgent case nor a genuine emergency.

The college, which represents doctors in emergency care, warned: “In our expert opinion, when an emergency department falls below 75% against the four-hour standard, it shows a significant level of overcrowding and begins to put safety at risk. Present figures suggest a substantial number of departments are falling below this level.”

The college believes that one in four A&E units are at risk of offering poor care, citing delays in assessing patients and administering pain relief.

In an emergency statement prompted by reports of intense pressure at A&E units around the NHS in England, Hunt said that the four-hour waiting time had to be revised to remove non-urgent cases.

“This government is committed to maintaining and delivering that vital four-hour commitment to patients,” Hunt said. “But since it was announced in 2000 there are nearly 9m more visits to our A&Es, up to 30% of whom NHS England estimate do not need to be there. And the tide is continuing to rise.

“So, if we are to protect our four-hour standard, we need to be clear it is a promise to sort out all urgent health problems within four hours, but not all health problems, however minor.”

NHS Providers, which represents hospital bosses, welcomed the change as “potentially helpful” in relieving the strain on A&Es.

But Jonathan Ashworth, the shadow health secretary, said: “Is he now really telling patients that rather than trying to hit the four-hour target, the government is now rewriting and downgrading it?”

Guardian 10^th January Rowena Mason and Denis Campbell