A nurse from Hereford accused of murdering seven babies at a neonatal unit has denied harming any children as she gave evidence for the first time.
Lucy Letby is also accused of 10 attempted murders between 2015 and 2016, allegedly using methods such as injecting air into the babies or poisoning them with insulin.
The prosecution alleges Letby was a "constant malevolent presence" in the neo-natal unit of the Countess of Chester Hospital in Cheshire.
The jury finally heard from the 33-year-old, seven months into her trial.
Letby trial latest: Alleged baby killer asked about 'I am evil' alleged confession note
She told Manchester Crown Court on Tuesday she had probably cared for hundreds of babies at the hospital.
Letby said it was "sickening" when she discovered she was being blamed for a number of baby deaths while doing the job she "loved".
"It was devastating. I don't think you could be accused of anything worse than that," she said.
Asked by her barrister if she ever did anything "meant to hurt any of them", she replied: "No, I only did my best to care for them."
Letby said she never wanted to harm any baby, saying it was "completely against everything that being a nurse is... I'm there to help and to care".
The defendant told the court about the three times she was arrested by police, on suspicion of murder and attempted murder of babies.
Among items recovered at her then home in Chester was a Post-it note found in a diary.
Among words written on the note were, in capitals, "I am evil I did this", the court has heard.
Letby also wrote: "I don't deserve to live. I killed them on purpose because I'm not good enough to care for them. I am a horrible evil person."
Barrister Ben Meyers KC asked her: "When you say killed them on purpose does that mean you've gone and done something intentionally?"
Letby replied: "No".
Asked to explain, she said it meant she hadn't "been good enough and that I've somehow failed in my duties and my competencies".
Letby said she'd written it because "I felt at the time I had done something wrong and I thought I'm such an awful, evil person... that I had made mistakes and not known".
Mr Myers asked: "What did you thought you had done?"
"That somehow I had been incompetent and I had done something wrong to affect these babies. I felt I must be responsible in some way," Letby replied.
She said the scrawled note "was a way of me expressing how I felt at the time that I wasn't able to say to anyone else".
Family of the alleged victims - who cannot be named - watched from the public gallery as Letby gave evidence, as did her own parents.
Letby, from Hereford, denies all the allegations.
The trial continues.