An RCN report revealed 37% of hospital staff delivered care in inappropriate settings, such as corridors, on their last shift.
Professor Nicola Ranger, acting RCN general secretary and chief executive, said: ‘The horror of this situation cannot be understated. It is a national emergency for patient safety and today we are raising the alarm.
‘Treating patients in corridors used to be an exceptional circumstance. Now it is a regular occurrence and a symptom of a system in crisis.'
Of those forced to deliver care in inappropriate settings, over half (53%) said it left them without access to life-saving equipment including oxygen and suction. More than two-thirds (67%) said the care they delivered in public compromised patient privacy and dignity.
The RCN called for mandatory national reporting of patients being cared for in corridors, to reveal the extent of hospital overcrowding, as part of a plan to eradicate the practice.
The nursing union is also asking its members to raise concerns when care in inappropriate settings takes place.
‘Corridor care is a scourge in our hospitals, but we know the solution is to invest in our entire health and care system - and its nursing workforce,' Professor Ranger added.
Saffron Cordery, deputy chief executive at NHS Providers, said: ‘No trust leader wants to treat patients in corridors, store cupboards or other non-clinical areas as it compromises quality of care, patient privacy and dignity.'
Cordery said the survey highlighted the ‘urgent need for more strategic investment and planning, adding: ‘It's vital the next Government properly address the root causes of hospital overcrowding. Improving social care and community services is also key to ensure patients can be discharged safely and promptly, freeing up hospital beds for those most in need.'