An update from the NHS Secondary Uses Services (SUS), seen by The Telegraph, shows that capacity is tracking as normal in October with the usual numbers of beds available that would be expected at this time of year, even without extra surge capacity.
An NHS source said: "As you can see, our current position in October is exactly where we have been over the last five years."
The new data shows that, even in the peak of the Covid outbreak in April, critical care beds were never more than 80 per cent full.
Although there has been a reduction in surge capacity since the first wave, with the closure of the emergency Nightingale Hospitals, there is still 15 per cent spare capacity across the country - fairly normal for this time of year.
It means Covid-19 patients are accounting for around 10 per cent of general and acute beds in hospitals, but there are still more than 13,000 beds available. In critical care, around 18 per cent of beds are still unoccupied, although it varies between regions.
However, even in the worst affected areas, such as North-West, only 92.9 per cent of critical care beds are currently occupied.
Commenting on the new data, Professor Carl Heneghan, director of the Centre for Evidence-Based Medicine at the University of Oxford, said: "This is completely in line with what is normally available at this time of year. What I don't understand is that I seem to be looking at a different dataset to what the Government is presenting.
"Everything is looking at normal levels and free bed capacity is still significant, even in high dependency units and intensive care, even though we have a very small number across the board. We are starting to see a drop in people in hospitals.
"Tier 3 restrictions are working phenomenally well and, rather than locking down, I would be using this moment to increase capacity."
On Saturday, Sir Patrick Vallance and Professor Chris Whitty warned at a press conference that bed usage would be exceeded on November 20, and even extra surge beds would be used up a few days later.
But the leaked documents also show that no intensive care units are in Covid-19 Pandemic Critcon levels above two, and the majority are at 0, meaning they are operating as normal.
Critcon levels three and four are enacted during a "full stretch" and "emergency", when other wards need to be used for critical care. But 146 units out of 222 (65 per cent) are still at "Critcon 0", which is defined as "business as usual" by the NHS.
Just 29 units (13 per cent) are at "Critcon 1", defined as the usual impact of a bad winter. And only 19 (eight per cent) are at "Critcon 2", described as a "medium surge". Twenty-eight units have not reported their position.
Speaking to the science and technology committee on Monday, Prof Whitty accepted that the number of struggling hospitals was "small, and we want to keep it that way".
Dr Ron Daniels, an intensive care consultant at Sutton Coldfield's Good Hope Hospital also said there had been a "slight dip" in in-patient numbers and people in intensive care units.
Dr Daniels also said figures show that far fewer patients now need ventilation (33.9 per cent as opposed to 72.1 per cent) and fewer are developing multi-organ failure.
The chief executive of NHS Wales said on Monday that the number of Covid-19 patients in Wales needing critical care is less than half what it was during the peak of the virus, despite rising cases.
Dr Andrew Goodall said early intervention by doctors, aided by increased testing and improvements with oxygen therapies, meant that demand on intensive care units and mortality rates were lower compared with April.
Demand for critical care capacity in Wales is 60 per cent lower than at the peak, with 57 people currently receiving treatment, while 1,275 people currently occupy hospital beds because of Covid-19 in non-critical care areas.
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