From the judges summary.
29. In both cases of poisoning, the prosecution relied upon the evidence of Professor Hindmarsh, a consultant in paediatric endocrinology. He gave evidence in the case concerning Baby F, that the blood test results demonstrated that he had been given exogenous insulin over a period of 17 hours and that the insulin had been administered at a constant level over that time. One bag which was already running had been spiked. Another bag of stock insulin had also been contaminated. The same person must have contaminated both as the level of insulin added to the two bags was similar. In the case of Baby L, Professor Hindmarsh said that the baby’s hypoglycaemia had continued from 9 April until around 15.00 on 11 April and that the only way in which the hypoglycaemia could have been induced was via the administration of insulin in the feed. He calculated that either 2 or 3 bags of fluid had been contaminated.30. At trial, the integrity of the blood samples and reliability of the biochemical testing was challenged by Mr Myers. However, in her evidence at trial, the applicant admitted that both babies had been poisoned by insulin, but denied that she was the poisoner. The prosecution relied upon the unlikelihood of there being two poisoners at work on the unit.