21 May 2013 Last updated at 06:14 ET
By Nick Triggle Health correspondent, BBC News
Pressures have been growing on A&E units for a number of years
A&E is on a “cliff edge”, NHS leaders say as MPs begin an inquiry into the state of emergency care in England.
The warning by NHS Confederation chief executive Mike Farrar comes as the Health Select Committee holds its first hearing on the issue.
He said if the pressures continued to grow, the workload would become “simply impossible” to deal with.
Meanwhile, the Independent reports that A&E chiefs in the West Midlands say they can no longer guarantee safety.
In a letter sent to NHS managers across the region and seen by the newspaper, emergency care managers said they were finding themselves in a position where the delivery of unsafe care was happening on “too frequent a basis”.
The latest warnings come after weeks of mounting concern.
The Care Quality Commission has already said it believes the rise in demand for A&E is unsustainable, while NHS England is carrying out a review of the problems.
Attendances have risen by 50% over the past decade, and this winter large parts of the health service started missing the four-hour waiting time target.
There have even been reports of temporary waiting areas being set up in hospital car parks and store rooms.
It has been described as the most challenging period for A&E for a decade.
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