text: The warning has been made by the Royal College of Emergency Medicine in its weekly update of A&E performance.
  It showed nine in 10 hospitals are increasing bed numbers - but despite this they have problems seeing patients quickly enough and discharging them.
  The RCEM weekly report provides a snapshot of performance.
  It covers more than 40 hospital trusts - one in five of the total.
  Special report page: For the latest news, analysis and video
  Nick Triggle: The lost beds problem
  Hugh Pym: The Northern Ireland challenge
  Winter across the UK:  A guide to how the NHS is coping
  Video: Why hospitals are under so much pressure
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  The update suggested that just over 86% of patients were seen and dealt with in four hours - below the 95% target.
  It also highlighted problems with delayed discharges - this is when hospitals cannot release patients because services or care are not available in the community. It said in some places a fifth of beds were being taken up by these patients.
  And it concluded that despite the best efforts of hospitals, winter was proving difficult and there was "insufficient capacity and capability" to respond to rising demand.
  Meanwhile, official data from NHS England, which also covers last week but does not include how hospitals are performing against the four-hour target, revealed visits to A&E were increasing.
  There were nearly 340,000 attendances last week, up from just under 328,000 the week before.
  But Dr Barbara Hakin, of NHS England, said despite the increasing pressures staff continued to "deliver a first-class service".
  "We are working hard to make sure all parts of the NHS are well prepared for the busy winter period," she added.
  Scotland is also providing weekly figures for its major A&E departments. It showed that up to the start of December just over 95% of patients were being seen in four hours.
  The latest data available in Wales covers October and in Northern Ireland, November. Both nations are missing the four-hour A&E target.
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target: A&E units across the UK are not equipped to cope with the rising demands being seen this winter, emergency care doctors say.