The BBC's Stephen Cape: "She pleaded guilty as her father listened close by"

Lousie Sullivan, 26, was warned by the judge that she could face a prison sentence when the court reconvenes in two weeks after her plea was accepted by the prosecution.

Detective Inspector Philip Wheeler, of the Metropolitan Police, said: "It was a very emotional case for my officers."

Mrs Jongen was in court on Monday

He attributed Sullivan's guilty plea to the professionalism of the police's case: "I'd like to believe we amassed such a strong case against her that she pleaded guilty."

Sullivan was accused of shaking to death six-month-old Caroline Jongen. She denied the charge of murder but admitted to unintentionally killing the baby, who died of head injuries and brain damage while in her care in April last year.

She said she had shaken the baby "a bit" after becoming concerned that the child had had a fit whilst being fed.

Retina filled with blood

However, the court heard from the prosecution that a post mortem had revealed that the child's retina had been filled with blood, indicating how severely the child had been shaken. The prosecution said that the child had definitely died as the result of shaking.

Ms Sullivan was a live-in nanny at the Jongens' London home

During Monday, Nigel Sweeney presented the case for the prosecution. He said Sullivan's admission to manslaughter amounted, in legal terms, to a plea to gross negligence.

Detective Inspector Philip Wheeler, Metropolitan Police, reacts to Sullivan's guilty plea

He said the Crown's case had been that "in the morning of 17 April last year, this defendant shook Caroline with severe force for a period which is difficult to quantify precisely but which must have been in order of five to 10 seconds".

Mr Sweeney said the evidence was clear that Sullivan loved the baby and the baby was confident and happy with her.

No premeditation

"This is not a case where there has ever been a suggestion of premeditation by the defendant," he said.

"She said she was feeding Caroline in the lounge and the baby either had, or she thought she had, some sort of fit or convulsion. That is why she grossly, inappropriately or negligently shook Caroline and thereby caused her death.

"That explanation would also amount to manslaughter on the grounds of gross negligence. She has pleaded guilty on one of the two very bases on which the prosecution were going to invite a conviction (for manslaughter)."

Pathologists had told the inquest into Caroline's death that she probably died of "shaken baby syndrome".

First Aid Courses

Mr Sweeney said Sullivan had told police that she had undergone a course in child care at the New South Wales Technical College, Sydney.

She had also told them that she had also passed two first aid courses run by the Australian Red Cross.

One of the courses had included learning the "shake and shout" technique to see if someone was conscious by gently shaking their shoulders.

But this could have no relevance to the scenario described by the Sullivan, he said.

Dutch-born financiers Marcel and Muriel Jongen had employed Sullivan to look after their only child at the family home in north London.

The case in several ways bears a striking resemblance to that of British au pair Louise Woodward, who was convicted of manslaughter over the death of eight-month-old Matthew Eappen.