2011 Stepping Hill Hospital poisoning incident

In 2011, a series of deaths and unexplained hypoglycemic episodes occurred among patients at Stepping Hill Hospital in Stockport, Greater Manchester, England. The investigation began after a nurse on a hospital ward noticed that several patients had unexpectedly low blood sugar levels. Subsequent inquiry suggested that saline ampoules and saline drips had been contaminated with insulin, a hormone that lowers blood glucose. Because the brain requires a constant glucose supply, excessive insulin can rapidly cause fatal hypoglycemia. Three deaths were initially attributed to the alleged contamination: George Keep, 84, Arnold Lancaster, 71, and Tracey Arden, 44, although each patient also had underlying medical conditions. On 21 July 2011, two further deaths were linked to the case, bringing the total to five. Greater Manchester Police (GMP) confirmed the inquiry would proceed as a murder investigation, deploying 60 detectives, armed guards at the hospital, and requiring staff to work in pairs when administering medication.

On 20 July 2011, GMP arrested 27-year-old nurse Rebecca Jane Leighton, who worked on the affected wards, in connection with the inquiry. She was charged on 22 July with multiple counts of criminal damage with intent to endanger life, criminal damage being reckless as to whether life was endangered, and theft, and was remanded in custody. On 2 September 2011, the Crown Prosecution Service dropped the charges against Leighton, stating it was "no longer appropriate" to continue as expected evidence had not materialised. Nazir Afzal, Chief Crown Prosecutor for the North West, said the original charges had been based on reasonable suspicion at the time. Leighton was later dismissed from her nursing post in December 2011, and an appeal against her dismissal was rejected in February 2012. By that point, police were investigating a total of 19 deaths at the hospital as possible poisoning victims.

On 5 January 2012, it emerged that a further death on 31 December 2011 had been linked to the investigation, and nurse Victorino Chua, 46, was arrested over claims that medical forms had been altered and a patient given extra medication. Chua was also questioned about the earlier deaths but was initially released on police bail without charge. By July 2012, GMP reported that 22 people had been poisoned and seven deaths had occurred in connection with the case.

On 29 March 2014, Chua was charged with the murders of Tracey Arden, Arnold Lancaster, and Alfred Derek Weaver, along with 31 further offences including grievous bodily harm and attempted poisoning. On 18 May 2015, following an 11-day jury deliberation at Manchester Crown Court, Chua was convicted of two counts of murder. He was acquitted of murdering Arnold Lancaster but was convicted of attempting to cause him and 20 other patients grievous bodily harm with intent through poisoning, as well as eight offences of unlawfully administering a poison with intent to injure. Mr Justice Openshaw sentenced Chua to life imprisonment with a minimum term of 35 years.