Police officers said she was described as "dazed and confused" by one Australian mother, Elisa Elwin, who dismissed her.

A second woman, Deborah Ayscough, from Sydney, sacked her after she caught her violently shaking her baby.

Sullivan was a qualified nanny with first aid certificates

A third employer, Elizabeth Afleck, dismissed Sullivan after finding her bouncing her baby instead of rocking it to sleep, while a family in England sacked her for being "dopey and incompetent".

Senior Detective Constable Matt Kehoe, of New South Wales Police, based in Sydney, said he interviewed Elwin, Ayscough and Afleck.

"They made it very clear they had not been happy with the treatment of their children," he said.

However, not all the comments of former employers were negative and some spoke in "quite glowing terms".

Sullivan praised

Australian journalist Marnie Lonsdale, who employed Sullivan, told the BBC: "She was fabulous. My girls liked her and she did what I asked her to. You can't have anymore than happy children."

In court, Sullivan changed her plea

All the statements were sent back to London to the investigating detective. No complaint had ever been made about Sullivan to the police in Sydney.

The case has brought renewed calls for a register of nannies and further criticism of the government's "tough" new measures.

Tricia Pritchard, of the Professional Association of Nursery Nurses, and Playpen, which campaigns for nanny registration, said: "After all the recent high profile cases, how long will it be before the government acts?"

"There needs to be a national register, incorporating proper inspection and rigorous police checks, of nannies.

"Childminders have to be registered, so why not nannies?"

Mrs Pritchard welcomed government moves to regulate nanny agencies, but said less scrupulous organisations would not have to join. The government proposals include a "kitemark" for nanny agencies so parents know they are reputable.

Register 'bureaucratic'

Margaret Hodge, junior education and employment minister, rejected the idea of a register for nannies as bureaucratic. But she said the kitemark system could be reviewed if necessary.

She said: "It is a voluntary system, but if it doesn't work then we will think about reviewing it."

Peter Cullimore, Chair of the Childcare section of the Federation of Recruitment and Employment Services, agrees that a statutory nanny register would be impractical.

He said: "I advise all parents wanting hired help to go through a registered agency."