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2011 Stepping Hill Hospital poisoning incident

SOLVED2011Stepping Hill Hospital, Stockport, Greater Manchester, England3 SOURCESUPDATED JUL 2026
Illustrative

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.

Key facts

Victims
George Keep, Arnold Lancaster, Tracey Arden, Alfred Derek Weaver
Date
2011
Location
Stepping Hill Hospital, Stockport, Greater Manchester, England
Case status
solved

Case timeline

  1. 2011-07

    Deaths and unexplained hypoglycemic episodes among patients at Stepping Hill Hospital lead to an investigation into insulin-contaminated saline.

  2. 2011-07-20

    Nurse Rebecca Jane Leighton is arrested in connection with the murder inquiry.

  3. 2011-07-21

    Two further deaths are linked to the investigation, bringing the total to five.

  4. 2011-07-22

    Leighton appears at Manchester City Magistrates' Court charged with criminal damage with intent to endanger life, reckless criminal damage, and theft.

  5. 2011-09-02

    Charges against Leighton are dropped by the Crown Prosecution Service.

  6. 2011-12-02

    Leighton is dismissed from her nursing job; police reveal 19 deaths are being investigated as possible poisoning victims.

  7. 2011-12-31

    A further death occurs, later linked to the investigation.

  8. 2012-01-05

    Nurse Victorino Chua is arrested over claims of altered medical forms and a patient given extra medication.

  9. 2012-02

    Leighton's appeal against her dismissal is rejected.

  10. 2012-07

    Greater Manchester Police state that 22 people had been poisoned and seven deaths had occurred in the investigation.

  11. 2014-03-29

    Chua is charged with the murders of Tracey Arden, Arnold Lancaster and Alfred Derek Weaver, plus 31 further offences.

  12. 2015-05-18

    Chua is convicted of two counts of murder and other poisoning-related offences at Manchester Crown Court.

Best coverage

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People

  • George Keep

    VICTIM

    84-year-old patient whose death was attributed to the alleged insulin contamination at Stepping Hill Hospital.

  • Arnold Lancaster

    VICTIM

    71-year-old patient whose death was linked to the poisoning investigation; Victorino Chua was acquitted of his murder but convicted of attempting to cause him grievous bodily harm.

  • Rebecca Jane Leighton

    ACQUITTED

    Nurse arrested and charged with criminal damage and theft in connection with the case; charges were dropped by the Crown Prosecution Service in September 2011.

  • Victorino Chua

    CONVICTED

    Nurse convicted in May 2015 of two counts of murder and multiple counts of poisoning-related offences; sentenced to life imprisonment with a minimum term of 35 years.

  • Tracey Arden

    VICTIM

    44-year-old patient whose death was attributed to the alleged insulin contamination; Victorino Chua was convicted of her murder.

  • Alfred Derek Weaver

    VICTIM

    Patient whose death led to a murder charge against Victorino Chua.

Roles reflect public records and court outcomes at the time of writing — supporting citations are on file under Sources.

Places

Stepping Hill Hospital, Stockport, Greater Manchester, England

53.3986, -2.1508

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Common questions

What happened to the victim?
In 2011, patients at Stepping Hill Hospital in Stockport, England, died after saline drips and ampoules were found contaminated with insulin, prompting a murder inquiry. A nurse, Rebecca Leighton, was initially arrested and charged but the charges were later dropped. In 2015, nurse Victorino Chua was convicted of two murders and other poisoning-related offences and sentenced to life imprisonment.
Where did the poisoning happen?
Stepping Hill Hospital, Stockport, Greater Manchester, England.
Who was convicted?
Victorino Chua (Nurse convicted in May 2015 of two counts of murder and multiple counts of poisoning-related offences; sentenced to life imprisonment with a minimum term of 35 years.).
What is the current status of the case?
Status: solved.
More cases in England

Sources

  1. ENCYCLOPEDIC2011 Stepping Hill Hospital poisoning incidentWikipedia · 2026-07-07
  2. PRESSContemporaneous coverage — BBC NewsBBC News · 2026-07-07
  3. PRESSContemporaneous coverage — Sky NewsSky News · 2026-07-07

Record history

First published
JUL 10, 2026