Police remain tight-lipped as investigation into suspected poisoning of patients at Blackpool Victoria Hospital continues

The probe began in November, with three nurses arrested – and bailed – and tests carried out on a number of deceased patients. Some funerals were even cancelled, families said.

In response to questions from The Gazette, Lancashire Police said it could not comment on the number of patients tested, nor on the number of families contacted.

It also did not say whether there have been any confirmed victims, though it said no bodies have been exhumed.

Detectives believed patients were being dosed with prescription-only pills to keep them heavily sedated during the night, it was understood, with the drug in question being Zopiclone.

According to the NHS, Zopiclone has to be ordered by a patient’s doctor and comes in tablet or liquid form. It is routinely prescribed and, when used properly, is safe.

Late last year, it was claimed up to eight former patients had been identified as possible victims, and families continued to be contacted as recently as last month, it was understood.