Charges against John Lee, 34, a registrar in paediatric anaesthetics, and Dermot Murphy, 34, a registrar in haematology, were dropped after it was revealed that the boy's death was caused by a "chapter of accidents and misunderstandings" at the London hospital rather than gross negligence on the doctors' part.
The doctors were charged with manslaughter of Richie William, who was receiving chemotherapy at Great Ormond Street in July 1997 for non-Hodgkin's lymphoma. But yesterday they left the dock at the Old Bailey after a prosecution witness changed his testimony.
Professor Alan Aitkenhead initially believed Dr Lee's conduct over the injection had fallen "seriously and significantly below that which could be demanded of him". But when he learnt of important failures in the system operated by the hospital, he changed his mind and the Crown Prosecution Service was advised by senior lawyers to drop the case.
Richie died five days after Dr Lee injected the drug vincristine into his spine instead of into a vein. Subsequent investigations revealed that the drug should never have been sent to the operating theatre. To avoid such an accident, hospital policy dictated that the drug should stay on a specialist cancer ward.
On the day of the injection, Dr Murphy was covering for an off-duty haematologist and Dr Lee talked to him on the phone. He asked him if it was straightforward and Dr Murphy confirmed it was, said Richard Horwell, for the prosecution. "[Dr Lee] did not check the route of administration either on the syringe label or on the documents in the room," added Mr Horwell.
Before formally finding the doctors not guilty, the Recorder of London, Michael Hyam, said the investigation had been useful because it "threw up a number of deficiencies in the administration of the hospital". The case should help to prevent "anything like this chapter of accidents arising again".
Richie's mother, Dolores William, said in a statement:"The medical profession should be accountable for their actions like everyone else. We are still devastated by the way Richie died. He suffered a great deal of pain in the days before his death because of the negligent treatment he received."
The hospital said it had accepted responsibility for the boy's death and was responding to a civil claim from the family.
Spinal vincristine injections have been linked to a number of deaths since 1990 including those of cancer patient Malcolm Savage, 16, who died after an injection at Peterborough District Hospital, Jean Coughlin, 56, at Middlesbrough General Hospital, and Percy Billington, a retired bank clerk, at St Bartholomew's, London.