Stepping Hill: Male nurse, 46, held after patients poisoned with contaminated drips

The arrest came as it emerged that the death of an 82-year-old man on New Year’s Eve is also now being investigated after his medicines were found to be contaminated.

His is the fourth death being investigated by police looking at the contamination of saline drips in June and July last year.

The nurse, 46, who was arrested at his home in Stockport yesterday, was held on suspicion of unlawfully administering or causing a person to take a noxious substance, or poison, after eveidence that medical records were tampered with on Monday.

Sources close to the investigation stressed that the arrest of the nurse forms part of a separate investigation to the four deaths, and as yet there is no link between the two.

But the arrested nurse worked on the same wards at the same time the patients were poisoned last summer.

Assistant Chief Constable Terry Sweeney, of Greater Manchester Police, said: “I must stress that at this time he is only being spoken to in relation to these matters and, as we have previously said, we will not and cannot rule out making further arrests in the coming days or weeks.

“I cannot stress enough just how complex an investigation this is and it is one that we continue to commit significant resources to.

“I know relatives of the confirmed victims affected and the public in general continue to seek answers and we are working as quickly as we can to provide them without jeopardising the quality or integrity of the investigation.” Police have yet to establish a causal link between the deaths of the four patients and the contamination of their saline drips.

The man arrested yesterday was held after another nurse noticed the medical records of a patient on Ward A3 had been altered overnight between Monday and Tuesday.

All four of the deaths took place on wards A1, A2 or A3 – acute care wards caring for seriously ill patients.

The patient who had his records altered was given medicine he should not have received but was not harmed. He was carefully monitored and subsequently discharged.

Stockport NHS Foundation Trust, which runs the hospital, said it was “appalled”.

Chief executive Chris Burke said: “We are appalled by the malicious intent of this act, but thanks to the skill and experience of our staff it was spotted and reported immediately, and most importantly we ensured no patient suffered any ill-effects.”

As part of the wider operation, detectives are investigating the deliberate contamination of products at the hospital after the blood sugar levels of patients on two wards dropped between 1 June and 15 July last year.

The suspect held yesterday was one of the 650 people already spoken to by police during their complex and long-running investigation at the hospital since the saline drip contaminations were discovered.

While treating the latest arrest as separate to the original investigation, sources said detectives will “follow the evidence” wherever it leads.

Previously, nurse Rebecca Leighton was arrested on suspicion of murder but released without charge six weeks later.

Charges that Ms Leighton tampered with saline solution with intent to endanger life were dropped by the Crown.