A society nanny accused of shaking to death a three-month-old baby walked from Liverpool Crown Court a free woman yesterday after the prosecution case against her collapsed.

Linda Wise, 47, who worked for European royalty, Greek shipping magnates and a host of wealthy, privileged or famous mothers, always protested her innocence of what she described as an “appalling crime”.

The prosecution alleged that she handled Isaac Rowlinson, the 13-week-old son of two Lancashire police detectives, so roughly that he suffered bleeding over his brain causing severe brain damage. He died ten months later from an epileptic fit.

Five weeks after the start of the trial, Mr Justice David Clarke ruled that the medical evidence presented to the jury was insufficient for the court to convict safely. The case has underlined the difficulties of achieving a successful conviction in “shaken baby” trials, and raised serious questions about whether the Crown Prosecution Service should have proceeded to court.

Mr Justice Clarke told jurors: “There are no winners in this case. The loss of the parents is incalculable and the defendant herself has been under a cloud of suspicion for a long time, and that cloud will not necessarily lift at once just because the trial is coming to an end.”

Paul Rowlinson, 41, a detective inspector, and his wife Lisa, 38, a detective constable, have been in the public gallery every day of the trial except one, when they attended their daughter’s sports day. They were notably absent as the judge directed the jury to return a not-guilty verdict. The couple employed Miss Wise through an agency shortly after Isaac’s birth because he was sickly and had difficulty keeping down his feeds. In September 2006 she stayed in sole charge of Isaac at the family home in Penwortham, Lancashire, while his parents left for an overnight break in the Lake District.

It was while she was alone with the baby that Miss Wise is accused of handling him so roughly that it prompted a brain haemorrhage from which he was never able to recover. Miss Wise, of Gaerwen, Anglesey, North Wales, denied manslaughter.

Mr Justice Clarke said that he had been “greatly troubled” by aspects of the medical evidence since halfway through the trial. He said that the prosecution had established the presence of three symptoms, notably subdural and retinal bleeding and encephalopathy, but this in itself is not enough to prove nonaccidental head injury.

The prosecution had sought to link Isaac’s injury to an incident involving a hospital visit several weeks earlier. However, medical experts were unable to agree with a prosecution claim that the injury happened while Miss Wise was in sole charge of the child.

Also, the judge concluded: “Any handling of a baby involves lifting and moving them about and some people may be less gentle than others but this does not constitute an unlawful act.”

After the hearing Miss Wise emerged from court beside Neil Hampson, her solicitor, and members of her family. There was little sense of jubilation. She acknowledged that her career as a nanny was effectively over.

Over her 25-year career she has worked for many rich and famous people, enjoying the millionaire life-style of her employers in New York, Switzerland and Monte Carlo. She has worked for the Greek shipping magnate Philippe Niarchos and his brother Spyros.

She has also worked for Tamara Mellon, the society figure and founder of the Jimmy Choo fashion empire, Santa Sebag-Montefiore, sister of Tara Palmer-Tompkinson, the philanthropist Sir Peter Lampl, and Prince and Princess Frankopan, members of the Croatian Royal Family. In a statement read by her solicitor she said: “The last two years of my life have been on hold because of a dreadful allegation made against me. I have dedicated the last 25 years to caring for babies and young children. I have never harmed a child in my care and would not do so and certainly did not harm baby Isaac.

“Despite the allegations made against me I have nothing but sympathy for Paul and Lisa Rowlinson. They have lost their beloved child and nothing will bring him back.

“I have been totally vindicated by the outcome today but the proceedings have effectively put an end to my career. I have been accused of an appalling crime that I did not commit.

“Now I have to pick up the pieces of my life and just want to work towards making a positive and productive future for myself.”

After the hearing, Helen Morris, who works on complex cases for the Crown Prosecution Service, defended the decision to bring the case to court. She said: “At the conclusion of his address to the jury the judge said that the criminal justice process comes out of this very well. I think the judge’s comments make it clear that the trial was properly brought.”

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