She murdered seven babies and attempted to murder six others in a neonatal unit at the Countess of Chester Hospital, in Cheshire.
The first five murders in all happened between June and October 2015 and - despite months of warnings - the final two were in June 2016.
In an interview, Dr Brearey claimed senior staff at the Countess of Chester Hospital were worried about reputational damage to the organisation.
He said that instead of acting on his warnings he and his colleagues lives were made very difficult - so much so that they felt under attack. "You go to senior colleagues with a problem, and you come away confused and anxious," Dr Brearey explained.
And he claimed his experience was not uncommon in the NHS. Dr Brearey said he had been contacted by clinicians across the UK "in the last three days" who tell him "clinicians raised concerns with senior members of the hospital and their lives were made very difficult by doing that".
"I can't emphasise enough how difficult a position this puts the clinician in," he went on to say. "Carrying out your clinical practice in that environment is very difficult."
The consultant added: "Doctors and nurses all have the regulatory bodies that we have to answer to, and quite often we'll see senior managers who have no apparent accountability for what they do in our trusts and then move to other trusts."
