"I know in my heart I did nothing wrong, and the people I love, and the people who know me, know that I'm not capable of that."
Louise Woodward (20), the former British au pair convicted of the manslaughter of Matthew Eappen, last night denied responsibility for his death.
She was speaking in a hard-hitting television interview designed to convince an increasingly sceptical public that she is innocent.
It was a conviction she said she did not deserve - even the trial judge, Hiller Zobel, knew the conviction was a "miscarriage - but he had done the best he could under the circumstances.
In her first television interview since the Supreme Judicial Court in Massachusetts upheld her conviction for manslaughter and allowed her to return to Britain last week, Woodward told BBC's Panorama programme she did not know the full truth about the circumstances of Matthew Eappen's death.
However, she said, somebody had to pay for his death, and if his parents did not cause his death "somebody has to pay and that somebody had to be me".
During a 45-minute interview, Ms Woodward appeared confident and at ease as she sat opposite the BBC reporter, Mr Martin Bashir, explaining the routine of the "strange" day on which Matthew Eappen was taken to hospital.
She admitted that she had shaken him to revive him, because she believed he had choked on his vomit; she was in a panic, but she was not rough with him.
Matthew was a "very sweet baby", he was "smiley, playful", but he had slept for most of the day and when she could get no response from him she tried "shaking him lightly" so he would regain consciousness.
Ms Woodward also spoke of occasions before February 4th - the day he became seriously ill - when Matthew Eappen "could have possibly hit his head".
The suggestion was that the injuries which led to his death may have been old ones and not caused by her shaking him. He may have hit his head, she said, when he "toppled over" close to a flight of stairs.
"The only thing that was on my conscience was that I may not have done enough, but I know I did everything I could, that everything I was capable of doing I did. I know that I did nothing to cause it," she told Panorama.
Recalling the health of baby Matthew, she said: ". . . Like I say he wasn't healthy and happy. He'd been showing symptoms for the previous few days before he went to hospital.
"I hardly saw Matthew on February 4th. He slept almost the entire day.
"When the jury came in, they didn't look at me, they were looking at the floor and their faces said everything really. It was frightening, and then they read the verdict. And I just couldn't believe it. I was so sure they were going to find me innocent.
"I don't think they (the jury) understood the medical evidence. I think it is incredibly difficult to try and explain neurosurgery and a doctor's life's work to an ordinary lay person and expect them to understand and be able to have two doctors giving two extremely different interpretations of the same piece of evidence and to expect a lay person to chose between the two I think is impossible."
About whether the support in her home town of Elton helped her she said: "Absolutely. It helped a lot, it really did. Just to know that people realised this was wrong, people who had watched the trial for themselves or at least part of it, could see this was wrong, and I got letters from all over the world, including America, even Bostonians could see this was wrong."
Told that she had been described as "cold" and calculating in the witness box, she said: "I guess maybe it is the British in me that I'm naturally restrained. I saw it as my big chance to tell everybody, and I did hold back with crying, because I was trying so desperately to tell my story, to tell what happened."
Recalling her shock at the murder verdict, she said: "I was so sure that if I told the truth, that they would believe me and that the medical evidence had proved everything, and that this was such an obvious miscarriage of justice that I was going to be released, and I just couldn't believe it."
Asked why she had not sent a message to the Eappens, she replied calmly: "I certainly have no love for them.
"They did their very best to get me in prison, I just don't feel there is anything I could say to them that they don't already know.
"I don't want to antagonise them, I don't want to get into a fight in the press with them."
Asked if she had any feelings for the fact that they lost a child she said: "Of course I do. I am not accusing anyone of anything, because I don't know what happened either.
"All I have ever been able to say is, I don't know what happened, but I know what didn't happen, and I can only ever tell you that."