The number of A&E units failing to meet the Government four-hour target has almost trebled in a year.
Some 39 departments failed to meet the target of seeing 95% of patients within four hours during the period July to September, according to NHS England data.
This compares to 14 units during the same period in 2012.
The target covers all A&E types, including minor injury units and walk-in centres, and the number discharged, admitted or transferred within four hours of arrival.
The NHS as a whole across England is still hitting the target, with 96% of all patients seen within the timeframe during July to September.
But this is only because some units perform way above the target, with some consistently hitting 100%.
In August, Prime Minister David Cameron announced £500 million of extra funding over the next two years to support A&E.
The cash is intended to help A&E units through the winter, cutting delays and reducing the number of admissions.
Shadow health secretary, Andy Burnham said: "David Cameron's ill-judged re-organisation has placed the NHS in the danger zone.
"These figures confirm he has presided over the first summer A&E crisis in living memory.
"The Government cannot continue to ignore the warnings. Until ministers face up to the fundamental causes - the collapse of social care and front-line job losses - the NHS will continue to struggle.
"This is further proof you can't trust David Cameron with the NHS. We can't have another year in the NHS like the last one - he needs to urgently get a grip."