Paul Farrell, 55, could face the rest of his life behind bars after admitting a campaign of sexual abuse against children across 35 years.
He worked as a porter at the famed central London children’s hospital between 1994 and 2020, though none of the victims were patients.
Wood Green crown court has heard how Farrell is believed to have preyed on children thousands of times, stealing toys from the hospital’s wards to give to his victims to keep them quiet.
He kept notes in his diary on how best to groom and manipulate his victims, the court heard.
The mother of three of Farrell’s victims delivered an emotional impact statement on Friday, revealing how her “heart had been ripped out” when the abuse was revealed.
“My life had been turned upside down and torn apart”, she said, holding back tears as she read out her statement.
“How did this happened in our home by a man who was trusted and a big part of our lives?”
She told the court she has been left questioning herself, wondering if she has “failed as a mother”.
But she vowed: “I will not allow this man to destroy my family. We are survivors, my boys will get through this and we will come out stronger.”
Judge Noel Lucas QC said it was clear Farrell manipulated his victims and their families, telling the woman: “He was clever about it, even to the point of leaving messages for himself on his phone.
“How could you not have known? It was designed for you not to know.”
Prosecutor Paul Douglass told the court Farrell had “effectively manipulated and groomed the whole family in order to get at the young boys”.
“He kept a diary in which he noted down his strategies to keep them under control”, he said.
“He reminded himself what presents to buy for various members of the family, and when and how to offer his services as a baby-sitter.”
One of the boys was given cash to keep quiet about the abuse, and was sent a text by Farrell telling him: “‘Don’t f**k this up or your life’s [sic] will be ruined love you to bits x.”
The boy told police he felt unable to reveal the abuse to his family, often sitting alone in the toilet crying and struggling with anger issues.
“I used to take my anger out on everyone else, but I know deep-down it’s my fault”, he said.
Describing repeated attacks by Farrell, he said: “It was like I was running from a person chasing me, like a massive animal. I have nightmares about him coming in.”
Another victim of Farrell told the court yesterday: “I want you to know that you are not going to break me. I am going to get over this and be the best man I can be for the community.” Two of the victims say they were taken to the linen closet at the hospital to be abused.
A spokeswoman for Great Ormond Street Hospital (GOSH) said their thoughts were with all the victims of “this horrendous abuse” and that Farrell had “admitted to a catalogue of truly awful crimes”.
She added: “His actions are in direct contrast to everything we stand for as a children’s hospital.
“We would like to reiterate what has been said in court; that Paul Farrell did not target children at GOSH.
“We urge anyone who has concerns about this case to call the helpline that we have set up with the NSPCC on 0800 101 996.”
Farrell has admitted at least 560 incidents of abuse between 1985 and last year.
He insists the eight victims he has admitted preying on are the extent of his offending, but Mr Douglass said there are suggestions in the evidence of more victims who have not yet come forward.
Farrell, from Camden, has pleaded guilty to 76 offences. He is due to be sentenced by Judge Lucas on Monday.