Thakane Mtetwa, 61, calmly performed CPR, raised the emergency alarm and fetched an oxygen cylinder in her attempt to save Elsie Skelton, Sheffield Crown Court heard on Tuesday.

Mtetwa and young care assistant Amy Richmond discovered the 86-year-old ex-Rotherham Council worker during a night shift at Maltby's Layden Court Nursing Home last October.

"Elsie had moved towards the edge of the bed and my concern was that she might fall," the South African defendant told the jury. "I moved her to the centre, and then there was a noise at the back of her throat."

"Her skin was pale. I took the flannel from Amy, wiped Elsie's face and started to do mouth-to-mouth respirations. I pulled the cord twice to tell the others it was an emergency."

Mtetwa said she stopped after four chest compressions - fearing she might fracture the frail Mrs Skelton's ribs - and instead started massaging her heart. After three or four minutes she went next door to collect an oxygen tank as a last resort.

"I felt that I wasn't making any headway with my own air," she told the jury. "She wasn't breathing on her own. And when I started giving her the oxygen, she gave one last breath."

Last week Miss Richmond took the stand for the prosecution, accusing Mtetwa of asking her to lie and cover up Mrs Skelton's death. They would have to say she went while being bed-bathed, the teenage assistant told the jury.

"I think what I said was 'how come she died while we were washing her?'" said Mtetwa. "Amy was just overwhelmed by the whole thing."

"Even if anything had happened, I would be the person who would bear the brunt of it all."

It was suggested by the prosecution that Mtetwa held Mrs Skelton 'in a headlock' for several minutes to kill her, during a window of opportunity when Miss Richmond was on away from the ward.

Mtetwa denies murder. The trial continues.