A widower has called for health boards to halt the use of Omnipod insulin pumps, as he fears one malfunctioned and killed his husband.

Paul McNairney, 39, died last month after the Omnipod delivered four days’ worth of insulin in less than an hour as he slept, according to data obtained by the legal firm Digby Brown.

However, the pump manufacturer, Insulet, said it had no “evidence of a device malfunction or performance issue” currently and stressed that safety is its top priority.

Mr McNairney received the pump on the NHS and is said to have been using it since July with no issues, until he was found hypoglycaemic by his husband in November, dying days later in hospital.

Digby Brown said police had seized the device and it is now being analysed by health experts.

Mr McNairney’s widower, Scott Craig, 42, fears more people could be affected by faulty Omnipods.

He said: “This device is used worldwide so people need to know what happened, as even a single avoidable death is one too many.”

Mr McNairney, diagnosed with Type 1 diabetes aged two, wanted an Omnipod – a wearable pump that delivers insulin automatically – as it removed the need for his four daily injections and came with a companion device to track data.

He completed the training required by the pod manufacturer, Insulet, based in Massachusetts, US, on July 12 started wearing the pod supplied by NHS Greater Glasgow and Clyde.

Mr Craig said his husband was “expert” at managing his condition.

On Sunday November 7, Mr Craig woke at around 7am and left his husband having a lie-in, checking in at 10.30am and finding him still in bed.

When he checked again two hours later, he found his husband pale and sweaty – signs of being hypoglycaemic.

He used an emergency glucagon syringe, which should have roused Mr McNairney within minutes, but there was no response.

He called an ambulance and on arrival at the couple’s home in the Gorbals, Glasgow, paramedics injected Mr McNairney with a massive dose of glucose, but he did not respond.

The lawyer was taken to intensive care at the city’s Queen Elizabeth University Hospital and was confirmed to have catastrophic and irreparable brain damage.

He died on November 10 after loved ones decided to turn off his life support.

Mr Craig said: “I don’t know how I’m meant to get over this – we only married five months ago.

“But as well as the loss it’s the questions that make things worse.

“I can’t shake from my mind the fact that I was sitting in the next room relaxing with the dog while my husband lay dying in silence.

“But there is no way Paul died because of an oversight on his part. None. It’s just not possible.

“He managed his condition his whole life and used syringes for years without issue but died within months of using this pod? This is more than coincidence.

“I need to know how this happened. Paul’s family and friends need to know. Other pod users need to know. We all deserve to know how things went wrong here.

“Health boards need to stop using Omnipods right now until their integrity, and the safety of users, can be guaranteed.”

Police Scotland seized Mr McNairney’s Omnipod, which Scotland’s prosecution service forwarded to the Medicines and Healthcare products Regulatory Agency (MHRA) for investigation.

An exact cause of death is still to be confirmed, but an early review from Digby Brown found concerning data from the Omnipod.

In a typical night the pod was expected to automatically administer Mr McNairney with 0.55 insulin units hourly and then 1.15 units at breakfast to balance blood sugar with food intake.

Digby Brown said pod data indicates that at 8.40am Mr McNairney was given a breakfast dose of 16.9 units – enough to put him in a coma.

The legal firm said the pod then administered three more doses of 17.05 units each in the next 48 minutes.

In total he is said to have received 75 units – the equivalent of four days’ worth of insulin, despite a working Omnipod being designed so it cannot deliver more than 30 units in one hour.

Mark Gibson, Digby Brown’s product liability head, said the firm, which is conducting initial legal investigations, will “continue to support [Mr McNairney’s] loved ones and help them get the answers they deserve”.

Insulet said in a statement: “Consumer safety is Insulet’s number one priority. Our products are highly regulated, and we have comprehensive controls and procedures in place to ensure the safety of our products.

“Insulet has been made aware of this unfortunate incident and is working with MHRA in the UK to obtain the device for further investigation.

“At this point, we do not have evidence of a device malfunction or performance issue.

“Further analysis will be conducted upon receiving the device.

“Insulet has been safely and effectively designing, manufacturing, and distributing the Omnipod® Insulin Management System for more than 15 years and it is safe to use as intended with a prescription.

“We extend our deepest condolences to Mr McNairney’s loved ones at this difficult time.”

A spokeswoman for the Crown Office and Procurator Fiscal Service said: “The Procurator Fiscal has received a report in connection with the death of a 39-year-old man in Glasgow on 10 November 2021.

“The investigation into the death is ongoing and the family will continue to be kept updated in relation to any significant developments.”

NHS Greater Glasgow and Clyde said in a statement: “Our thoughts and condolences are with the family and loved ones of Mr McNairney as they continue to mourn his loss.

“An investigation into the death by the Crown Office and Procurator Fiscal Service is ongoing and, as such, we are not able to comment further at this time.”

Police Scotland declined to comment.