Stepping Hill Hospital in Stockport (Pic: Getty Images)

Stepping Hill Hospital in Stockport (Pic: Getty Images)

A nurse at the centre of alleged saline tampering at a hospital has been sacked, sources have confirmed.

Rebecca Leighton, 27, was released without charge six weeks after being arrested on suspicion of murder when patients at Stepping Hill Hospital in Stockport, Greater Manchester, were poisoned.

Charges that she tampered with saline solution with intent to endanger life were dropped by the Crown Prosecution Service (CPS).

The Nursing and Midwifery Council later lifted its suspension of Miss Leighton, who has always denied the allegations, and said she could return to Stepping Hill if the hospital approved.

During the NMC disciplinary hearing she admitted to the theft of opiate-based drugs but said they were for her own use to treat a throat infection.

It emerged today that she has been sacked following an internal disciplinary hearing at Stepping Hill into the drug thefts.

Stockport Hospital Foundation Trust has declined to comment as it is understood Miss Leighton has the right to appeal before the decision is finalised.

Miss Leighton spent more than six weeks in custody but was freed on September 2 after proceedings against her were discontinued due to insufficient evidence.

The alarm was first raised by hospital staff on July 12 when a higher than normal number of patients were reported to have "unexplained" low blood sugar levels amid fears that saline solution had been contaminated with insulin.

Meanwhile, Greater Manchester Police (GMP) said today that they have completed the first phase of their inquiries and revealed they have now determined that 19 people were unlawfully administered insulin.

In October, detectives said they were looking at around 42 potential victims who may have been harmed by the contaminated solution.

Detectives and medical experts have reviewed those cases and have now concluded that 19 people were unlawfully poisoned and 21 patients have been eliminated from the inquiry. They have not been able to determine whether two other patients who suffered hypoglycaemic episodes did so naturally or from poisoning.

Among those confirmed poisoned are Tracey Arden, 44, Arnold Lancaster, 71, and Derek Weaver, 83, who all died at the hospital.

All three were unlawfully administered insulin but tests are still ongoing as to whether the poisoning contributed to their deaths.

The investigation is currently focusing on incidents of hypoglycaemia on two wards at the hospital between June 1 and July 15 this year.

Experts with specialist medical knowledge have been drafted in to assist the investigation and 650 key and significant witnesses have been interviewed by police, GMP said.

Assistant Chief Constable Terry Sweeney said: "From day one we knew this would be an immensely challenging inquiry - and that continues to be the case - but we are now beginning to see the wood from the trees and have effectively completed the first phase of our investigation.

"I know victims and the relatives of those poisoned as well as the wider public and those at the hospital want answers and we are working as quickly as we can without jeopardising the quality or integrity of the investigation.

"I cannot stress enough just how complex and difficult this investigation is. We are continuing to carry out detailed forensic and medical inquiries and these take time and cannot be rushed.

"It is important the public understands that this is not something that can be done over the space of several weeks or even months but rest assured we are determined to identifying whoever is responsible and continue to commit significant resources to the investigation.

"For obvious reasons I cannot go into detail about the ongoing work we are doing suffice to say this continues to be a search for the truth.

"To that end we are making good progress and that is in no small part down to the meticulous work of my staff and the excellent co-operation we have had from everyone at Stepping Hill Hospital."