A Filipino male nurse was jailed for life with a minimum of 35 years on Tuesday for poisoning 21 patients with insulin at a British hospital, two of whom died.

Victorino Chua, 49, injected insulin into saline bags, ampoules and other healthcare products while working on two wards at Stepping Hill Hospital, near Manchester in northwest England, in June and July 2011.

When other nurses unwittingly used the products, the mostly elderly patients on the ward suffered sudden illness as they overdosed on insulin.

Chua was found guilty of murdering two of the patients, Tracey Arden, 44, and Derek Weaver, 83, and also causing grievous bodily harm to a third, Grant Misell, 41, who was left brain damaged.

Sentencing Chua at Manchester Crown Court, judge Peter Openshaw said: "He has committed a dreadful crime and he must now pay the price."

Relatives of some of the victims sat in silence in the public gallery as the verdict was delivered. Chua, dressed in a brown coat zipped up to his neck, showed no emotion.

The hospital called in the police to look into the surge of illness on the ward, prompting Chua to change tack by sabotaging prescription charts.

One patient was given an increased drugs dose as a result but recovered.

Chua was arrested in January 2012, and after a three-month trial, was on Monday found guilty on two counts of murder, one count of grievous bodily harm and 22 counts of attempted grievous bodily harm among other charges.

Detectives had described the father of two as a narcissistic psychopath and said he had shown a complete lack of remorse for his crimes.

Chua described himself in a letter found at his home as "an angel turned into an evil person", writing that "there's a devil in me."

"What he did was inexplicable and irrational," the judge said in his sentencing remarks on Tuesday.

"It is a striking, sinister and truly wicked feature of the case, he did not personally administer contaminated products directly to most of these patients.

"But having left saline bags contaminated with insulin he did not know which nurse would unwittingly collect them and still less to which patient the nurse would then unwittingly administer the poison.

"It is as if he left it to fate to decide who would be the victim."