Jasmin Schmidt, 34, who has previously worked for an A-list celebrity, lost her temper with the baby boy during a "restless night" and shook him violently, the Old Bailey heard.

The child's horrified parents, who run a designer clothes shop in North Yorkshire and were in the capital to attend London Fashion Week, took their son to hospital after finding him "limp and lifeless" after attending a function.

The force of the shaking had caused tiny veins between his skull and brain to tear and bleed and he had a fractured right elbow bone, which had occurred in the 24-hours before his admission to hospital.

Schmidt, a qualified pediatric nurse from Bonn, Germany, had been hired to look after the baby during 2002's London Fashion Week, while his parents shopped for stock.

The couple found their child "whimpering" in his cot.

Thanks to swift medical intervention the brain injuries proved only temporary and he was released from hospital. He is now a fit and healthy six-year-old boy.

Schmidt had worked for a number of wealthy families in and around west London after arriving in the UK in 1998. Her clients included a famous pop star, who cannot be named.

She was unanimously convicted of two counts of inflicting grievous bodily harm by a jury at the Old Bailey last month. Jailing her yesterday, the judge Mr Recorder Jeremy Gold QC said: "As you have never revealed what you did to him I cannot rule out that these injuries were inflicted by you in an outburst of violence resulting from a loss of temper or a lack of sleep or both.

"I'm satisfied that you used a degree of force that any sensible person, let alone a qualified paediatric nurse, would have inevitably realised was bound to have caused injury to a delicate and precious infant.

"It was an act of genuine cruelty and you should be ashamed. You are obviously not ashamed because you continue to deny responsibility."

Schmidt, who showed no emotion as she was jailed, was also banned from working with children for life.

It can now be revealed that she was cleared of causing actual bodily harm to a two-month-old baby girl between in 2006 and a three-month-old boy in 2003.

The North Yorkshire couple, who cannot be named for legal reasons, came downstairs one morning to find Schmidt already dressed and ready to leave. The nanny said not to disturb the child as he was sleeping after a restless night where he had been "angry" and needed several "quite hard" taps to settle down.

When the baby woke some 20 minutes after Schmidt had left, his skin was blue, he was pale and his head was cold to the touch. "He felt limp and lifeless," said prosecutor Sally Howes QC. "The change in him from the night before was dramatic."

Giving evidence, the child's tearful mother told the court: "I could tell he was very poorly. Every inch of me was wanting him to be OK, but I could tell he wasn't and he was becoming more lifeless and closing his eyes. He was continuing to close his eyes and I just kept shouting to keep him awake."

Happily his condition stabilised in hospital and he was transferred to Harrogate District Hospital where he was discharged on September 30.

Schmidt, of South Hampstead, London, denied two counts of causing grievous bodily harm on the same night.

She was jailed for three years for each offence and the sentences will run concurrently with each other.