A child with cancer died after contracting an infection linked to a contaminated water supply at Scotland's largest hospital, a whistleblower has told an MSP.

The allegations, relating to a case from 2017, were made to Anas Sarwar and have been described by the Labour politician as a "heartbreaking human tragedy".

The child's parents were reportedly not told about the link, which emerged following investigations into infections in children in the cancer wards at the Royal Hospital for Children (RHC) in Glasgow two years ago.

Two wards at the RHC were closed last September and patients moved to the adjoining Queen Elizabeth University Hospital (QEUH) as Health Protection Scotland (HPS) investigated water contamination incidents.

An HPS investigation found 23 cases of blood stream infections with organisms potentially linked to water contamination were identified between January 29 and September 26, 2018.

The Daily Record reported a clinician-led team at NHS Greater Glasgow and Clyde investigated further back than 2018.

The whistleblower who contacted Labour MSP Anas Sarwar claimed this investigation found up to 26 cases of water supply infections in children in the cancer wards in 2017, and that one child with cancer died after contracting an infection.

Glasgow MSP Sarwar called for a "full public apology" and said: "I have had information shared with me which shows that senior managers have been repeatedly alerted to the fact that a previous review failed to include cases of infection related to the water supply in 2017.

"Central to this whistleblowing evidence is that one child died and, to this day, the parents have never been told the true cause of their child's death.

"That isn't just a scandal, it is a heartbreaking human tragedy.

"I have had difficult information shared with me by patients and clinicians many times before, but this felt different. I immediately imagined how I would feel if that was my child, if I was that parent. I would want to know - I would expect answers."

Sarwar raised the issue at First Minister's Questions and called on Nicola Sturgeon and the health secretary to personally intervene.

Sturgeon said: "Patient safety is paramount and that's exactly why the Health Secretary commissioned the independent review into the design, build, commissioning and maintenance of the QEUH and it's also why, on September 18, a public inquiry into the issues at the hospital and the Sick Kids Hospital in Edinburgh was announced.

"We are determined to address the concerns of patients and families and the Health Secretary is committed to returning to Parliament to set out the full details of the public inquiry as soon as possible."

NHS Greater Glasgow and Clyde insisted its "overriding priority" is the safety of its patients, and that tests have shown the water supply is safe.

A spokesman added: "We rigorously review all cases of infection to ensure that our patients are appropriately cared for.

"We also completed an additional clinical review of the cases from 2017 in July 2019. This was carried out by senior clinical staff and it was concluded that no further action was required.

"Further to this, we have been working closely with external advisers Health Protection Scotland, assisted by Strathclyde University, on a review of cases of infection over a period from January 2015 to September 2019 and this report is due imminently.

"It is important to make clear that the water supply to the Royal Hospital for Children and Queen Elizabeth University Hospital is safe to use."

It said "extensive measures" have been put in place and the water has been assessed by an independent expert who confirmed it is "wholesome", meaning it is safe to use.

The NHS said when a patient dies, clinical teams discuss with family members the cause of death and the factors that have contributed to this, where they are known.

On Thursday the health board said: "When a patient dies in our care, our clinical teams discuss with family members the cause of death and the factors that have contributed to this, where they are known.

"Patients who are very sick are prone to infections and we closely monitor all infections to ensure patients are appropriately cared for. In 2017, we investigated two individual cases of Stenotrophomonas which were not linked. We reported these cases both to the national expert body, Health Protection Scotland and to our Board.

"These cases were also reviewed again in July 2019 when the clinical view was that no further action was required.

"At the time of the initial investigation into these cases, national guidance did not include a requirement for health boards to test for Stenotrophomonas in the water supply.

"Stenotrophomonas is widespread and is present throughout the general environment. As no tests were carried out at the time, it is not possible to conclude that these infections were connected to the water supply. It is extremely disappointing therefore that a whistle-blower has made this claim causing additional distress to families and to other families of cancer patients."