By Nick Triggle
BBC News, health reporter
Like all student nurses, Nicola Chambers was trying to learn from the senior nurse she was working with.
They were attending about a dozen patients on a surgical ward in a hospital in the east of England when they noticed a patient with pneumonia was having breathing difficulties.
It was clear the man needed help, but just at that moment her colleague fainted and was taken to A&E.
Just two years into her training, the 20-year-old was left alone to care for the patients, one of whom was getting into serious difficulties.
"I felt scared and very vulnerable. It is not a position student nurses should be in.
"Nurses are supposed to be extra, we should not be covering for staff, but that was what was happening.
"There was a physio who was around, but they were not meant to be in that position either."
Ms Chambers had to care for the man for about 30 minutes before the critical care team arrived to take him away to the intensive care unit.
"I did the best I could and of course that meant I was not really able to see to the other patients, but it was not a nice position to be in."
She refused to say what happened to the patient, but added: "I think resources are so over-stretched that nurses don't have the time to spend with students.
"I am not blaming them, because they are seeing to patients."
Student nurses are meant to spend 40% of their time with their mentors - qualified nurses that are supposed to act as their adviser when they are working on the frontline.
But Ms Chambers said this does not happen in practise. "I would guess I spend about 20% of my time with my mentor."
Fellow student Chris Brown, from Belfast, agreed students were often left alone.
"It normally seems to happen during meal breaks for 30 minutes or so or when patients are being transferred to another hospital."