Prosecutors had alleged Linda Wise, 47, shook Isaac Rowlinson when he was just 13-weeks-old and caused him brain damage.

Isaac, the son of Lancashire Police detectives Lisa and Paul Rowlinson, died 10 months later after suffering an epileptic fit.

Wise, of Gaerwen, Anglesey, North Wales, had denied manslaughter at Liverpool Crown Court.

Mr Justice David Clarke said for some weeks he had been "greatly troubled" by the prosecution evidence.

Among other reasons, he said, in his view the jury could not reasonably conclude that the bleeding on Isaac's brain took place in the time frame prosecutors alleged.

Miss Wise, who has worked for the actor Ed Stoppard, Greek shipping magnate Philippe Niarchos and a number of minor European royals, closed her eyes as the jury foreman gave the not guilty verdict.

Outside court her solicitor Neil Hampson read out a statement on her behalf. It said: "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 never do so. And I 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 but the prosecution has effectively put an end to my career in healthcare."