Staff at a hospital in Portsmouth recognised that the standard of care at the facility is "unacceptable" but felt "a culture of helplessness" prevented them from doing anything about it, according to health inspectors.
The Care Quality Commission (CQC) rated Queen Alexandra hospital as "inadequate" for its urgent and emergency services.
CQC inspectors, who visited the hospital unannounced in February and March, found the overcrowded A&E department was putting patients at "unacceptable risk".
They noted "regular, significant and substantial overcrowding" in the emergency department with patients being forced to wait for care in corridors and in ambulances.
The inspectors report noted ambulances were unable to get to other patients with life threatening injuries in the appropriate time and outlined how CQC officials even had to intervene at some points to ensure patients were safe.
During one inspection the A&E department was so busy that 16 ambulances - one-third of the emergency ambulance fleet for Hampshire - were queuing outside.
To free up ambulances some patients were forced to wait in a 'Jumbulance' - an ambulance vehicle that could accommodate up to four waiting patients - which inspectors said was "cold and unsuitable for the purpose for which it was frequently being used".
The CQC ordered the trust to make a series of improvements to emergency care, including stopping using the so-called 'Jumbulance' unless there is a major incident.
Responding to the inspection report, Portsmouth Hospitals NHS Trust's interim chief executive, Tim Powell, apologised for "failing" its patients.
Portsmouth Hospitals NHS Trust's chief executive Ursula Ward resigned in May.