NHS Providers said that last year NHS trusts and frontline staff made “extraordinary efforts” to maintain services for patients in spite of a relentless rise in demand and the worst flu strain in seven years.
But it said that, nevertheless, for many patients the quality of care fell short of what is expected, and it warned that the challenges this winter are likely to be even more severe.
Last winter saw medics describe corridors overflowing with patients, with more kept waiting in ambulances outside A&E departments and non-urgent operations postponed as staff worked to clear the backlog.
The report, which is based on published national data and the views of trust leaders, suggests factors that mean this winter could be even worse include a continued acceleration in demand for care, which has been significantly outstripping planning estimates.
A&E performance has also been worse so far this year compared to last.
It cited a greater pressure across mental health, community and ambulance services, higher levels of staff vacancies, and pressure across all other hospital activity restricting the ability to prioritise urgent care.
Last winter will also have led to a more tired and pressured workforce, making it more difficult than last year to fill extra shifts.
And it said social care is now in a weaker state, even when the recent extra £240 million in funding is accounted for.
NHS Providers, which represents health service acute, ambulance, community and mental health services, said it welcomed improvements that have been put in place by trusts.
It said factors pointing to better care this year include the impact of £145 million extra capital funding for buildings and equipment, the £240 million extra funding for social care, and the significant progress made in reducing delayed transfers of care for patients who are ready to move on from hospital.
It also said there was potential for a less severe flu season.
The report calls on NHS national bodies to acknowledge and plan for the scale of extra, more complex demand that health and care services face.
It added that as trusts work to recover NHS constitutional performance standards they will need adequate time and resources to get back on track.
And it demands urgent steps to address immediate workforce problems, and measures to provide a sustainable long-term solution.
NHS Providers deputy chief executive, Saffron Cordery, said: “Trusts and their staff put in extraordinary efforts last year to meet record demand - demand which continues to grow every winter.
“Despite measures to prioritise emergency care, it was clear that in many places the quality of care for patients feel short of what the public rightly expects.
“As attention turns to what this winter will bring, there are many improvements which have been put in place to welcome.
“Extra funding for capital projects and additional social care funding has enabled some trusts to better prepare and will provide some help in ensuring patients who don’t need to be in hospital have appropriate care at home or in the community.
“But there are clear warning signs. Performance is in a worse position going into this winter than last. Staff shortages are growing, putting additional strain on a workforce already overstretched during an exceptionally busy summer.
“The NHS remains under significant financial pressure with the additional funding announced by the Prime Minister only due to start flowing from next April. And the loss of dedicated winter funding has restricted what trusts can do to prepare for the most challenging time of the year.
“All things considered, trusts fear that this coming winter will be more difficult than the last.
“We must escape the current and unsustainable cycle of severe winter pressures, which leaves the service playing catch up throughout the rest of the year.
“The long-term plan represents an opportunity to do this but we must be realistic about what resource is needed, and where it is needed, to meet future demand and recover performance.”
Donna Kinnair, acting chief executive and general secretary of the Royal College of Nursing, said: “Staff are doing all they can, but demand is outstripping supply and winter 2018 could be the one that brings services to a standstill.
“The signs in the Providers’ report are ominous - increasing demand, worsening A&E performance and a yawning chasm in nurse numbers.
“Despite our warnings, the Government has still not acted to fill the 41,000 nurse vacancies in England alone. This means we go into winter with understaffed services, gaps in hospital rotas and a workforce that is more under pressure than ever.
“Staff across England have given almost all they can - nurses tell us they cannot keep this up indefinitely.
“Budget day is approaching and the £20 billion promised to the NHS presents a unique opportunity to respond to the clear signals that patient safety is at risk.
“This is the chance for the NHS and Government to work together to produce a fully funded workforce plan, with investing in nursing higher education as a priority.”
A spokesman for the Department of Health and Social Care said: “We recognise winter can be challenging, but as the report itself notes, the NHS will benefit from a second year of better, enhanced, national level winter planning, as well as £420 million to redevelop A&Es, improve emergency care and help get patients home quicker.
“The most recent performance statistics show that despite an increase in demand, hardworking and dedicated staff ensured that nearly 2,000 more patients a day were seen within four hours in September compared to the same month in 2017.”