Patients in A&E are facing unnecessary delays and confusion over access to emergency care, according to a new report.
In the most comprehensive review of NHS emergency and urgent care services, the Healthcare Commission found wide variations in how patients across England are treated.
People are confused over where to seek help, face unnecessary delays on being admitted to hospital, and some out-of-hours care is poor, it said.
More than one in three out-of-hours services cannot demonstrate that they meet national requirements on assessing patients within a set time-frame.
The Commission also found that the proportion of calls prioritised as "urgent" in out-of-hours care varied from under 4% to more than 32% between services, "raising questions" over consistency.
There were also fears over how quickly patients taken to A&E in an ambulance start receiving care.
In some A&E departments, for 95% of the time, ambulances are back on the road within 15 minutes of delivering a patient, but in other departments this figure is as low as 10%.
Overall, 50 (33%) primary care trust (PCT) areas were ranked "best performing" in urgent and emergency care, 41 (27%) were better performing, 33 (22%) were fair performing and 28 (18%) were least well performing.
However, the Commission did note improvements in some areas, with a rise in the number of people treated at A&E within the four-hour Government target, from 91.2% in 2003/04 to 97.9% in 2007/08.
Anna Walker, chief executive of the Healthcare Commission, said: "How an area deals with emergency and urgent care is absolutely a cornerstone of 21st century care. There remains issues for patients about access to these services."
