Hospitals are already as much as 99% full as the NHS braces itself for the winter – far over the 85% limit experts say must be maintained to protect patient safety.

Hospital trust chief executives have disclosed that they are running at close to 100% bed occupancy even before the expected bad weather and major flu outbreak this winter have arrived.

NHS bosses speaking on condition of anonymity also voiced fears that patients could be harmed and staff left unable to cope with the seasonal surge in demand for care because their hospitals could run out of spare beds.

“We’re lucky to get below 99% bed occupancy rates,” said the chief executive of one trust. “We plan for winter all year round, but there’s an underlying lack of beds and resources. There is a daily battle [over where to care for patients who need to be admitted] due to the lack of beds.”

The chief executive admitted to being worried about a chronic lack of beds risking patients’ health. “In terms of extreme pressure, we do worry. We worry about getting people into beds quickly enough.”

Another trust chief executive said: “We’re at 98% capacity and 11% of our beds are occupied by delayed transfer of care patients [who are medically fit to be discharged but cannot leave as social care support is not available]. Every day we have 80 to 90 patients in beds who should be somewhere else.”

The combination of bed shortages and what the NHS calls Dtocs is a real concern owing to its potential impact on the quality of care, the boss added.

Health experts internationally agree that if more than 85% of beds are occupied there is a greater risk of patients acquiring infections such as the Clostridium difficile and MRSA superbugs, ending up on wards not suitable for their illness and receiving inadequate care.

The NHS admitted last month that a £1bn drive to free up 2,000 to 3,000 hospital beds in England by this autumn had failed. The initiative has significantly reduced delayed transfers of care in only a few areas, it has been claimed.

Hospital bosses are also worried that a growing shortage of beds in care homes is denying them the chance to in effect expand the number of patients they can care for by paying care home operators to look after some elderly people – a tactic some use in winter to relieve pressure.

Chris Hopson, chief executive of NHS Providers, which represents hospital trusts, said: “It is worrying to hear of occupancy rates in some places moving close to 100% before winter has started.”

“The health service may be sorely tested in the coming months as it is already at or close to full stretch.”

Hopson said that while the government’s recent £337m injection of emergency funding was welcome, it had come too late to make much difference to hospitals’ winter planning.

NHS Providers has also warned in a report published on Thursday that the health service is critically short of paramedics, GPs, A&E doctors and nurses.

Dr Chaand Nagpaul, chair of the BMA: ‘High levels of bed occupancy will make it difficult for many hospitals to provide beds to ill patients who desperately need to be admitted.’ Photograph: BMA

NHS leaders say they fear that staffing agencies may exploit the late arrival of the government’s emergency funding and the health service’s serious staff shortages to increase the rates they demand for supplying doctors, nurses and other personnel.

“These figures are deeply worrying and show an NHS which is now struggling to find free beds year round. The UK already has fewer beds than equivalent European nations and further cuts could exacerbate pressures, which will adversely impact patients,” said Dr Chaand Nagpaul, chair of the British Medical Association.

“Bed occupancy remains higher than recommended safety levels of 85%, and this is added to by lack of capacity in community services and social care. High levels of bed occupancy can increase the risk of cross infection between patients, and will make it difficult for many hospitals to provide beds to ill patients who desperately need to be admitted.”

A spokesman for NHS Improvement, which regulates hospital performance, said: “The NHS is under great pressure, bed occupancy is very high in some areas and its staff are owed a huge thank you for working so hard for patients in these circumstances.

“Planning for this winter has been more effective and more extensive than ever before. We would always encourage the public to consider alternatives to going to hospital wherever possible, including their local GP or pharmacist.”