The scandal-hit Glasgow health board must be put into special measures, Anas Sarwar has demanded, following an alleged cover-up of Milly Main's death.
The 10-year-old girl was in remission from leukaemia before contracting a fatal infection while in the Queen Elizabeth University Hospital (QEUH).
NHS Greater Glasgow and Clyde (NHSGGC) have said that they were not obliged to test for bloodstream infection Stenotrophomonas - listed as a possible cause on the child's death certificate - at the time of Milly's death and could therefore not determine whether the infection was linked to their water supply.
However, Milly's mother has said she is "100%" certain contaminated water caused the infection and told the BBC she feels "let down" and "lied to" in the wake of her daughter's death.
Scottish Labour MSP Mr Sarwar has now said the health board must be put into "special measures", accusing it of "threatening and intimidating" the whistleblower who claimed that Milly's death was caused by contaminated water at the QEUH in 2017.
Mr Sarwar raised the whistleblower's claims that a doctor-led investigation uncovered a further 26 cases of Stenotrophomonas in child cancer patients at the hospital - in addition to the 23 found by an official investigation - with the First Minister and Health Secretary, and has now called on the government to act.
Describing NHSGGC as "not fit for purpose", Mr Sarwar said: "The Glasgow health board has unforgivably let down patients and staff.
"There was an attempted cover-up of Milly's death, and there are still dozens of families who don't know the truth about infections contracted in the QUEH.
"This only came to light following the brave actions of an NHS whistleblower.
"But rather than seek answers for patients and the public, the health board has resorted to attacking the whistleblower, threatening and intimidating them.
"This is a clear attempt to silence staff from speaking out, and prevent the truth being heard by the public.
"Who is signing off these insulting statements being issued by the health board and are they being cleared by the Health Secretary?
"The Scottish Government must now step in and put the health board into special measures, so that ministers take control, staff can speak out in confidence they will not lose their jobs, and - most importantly - parents can learn the truth.
"NHS Greater Glasgow and Clyde is not fit for purpose."
Not treated as public matter
The cover-up allegations have led to calls for Health Secretary Jeane Freeman to resign.
In a statement on Friday, Ms Freeman said that three days after she announced an inquiry into infection at the hospital on September 17, a parent contacted her to tell her of their child's death after treatment at QEUH in 2017.
She said she wrote back on October 23 expressing condolences, saying she had asked senior NHSGGC staff to contact the parent and checked later this had been done.
Ms Freeman added: "I am at all times aware of the importance of patient confidentiality and so rightly, I believe, I did not treat this correspondence as a public matter.
"The ward in which the child concerned in the correspondence I received on 20 September, 2A/2B, was closed and undergoing remedial and upgrading work.
"Any suggestion that children were at risk after I received this information is therefore incorrect."
"The water in the hospital is safe"
A NHSGGC spokeswoman said: "This week's coverage will have been very challenging for Milly's family. It is a tragedy in any situation when a young child dies. We would again like to share our deepest condolences with the family involved.
"We have offered to meet Ms Darroch to discuss her concerns, and to answer her questions where we can.
"We fully understand that the family wants to know whether the infection Milly had is connected to the water supply.
"The truth is there is no way to know this as we did not consider this to be the source at the time and we did not test for the particular infection in the water supply.
"We remain very concerned that a member of staff has made a claim of a link when there is no evidence of this, causing significant distress and anxiety to Milly's parents.
"The water in the hospital is safe and has been independently assessed as such."