Council officials said they did not know that Baby P's mother had a boyfriend
The little boy, who until last week was only known as Baby P, is once again back in the news.
On Friday, his mother's 32-year-old boyfriend was found guilty of raping a little girl. The 27-year-old mother of Baby P was acquitted by a jury of child cruelty charges.
And 21 months after his death, the court has said that the toddler can now be identified by his first name - Peter.
The mother's boyfriend, who still cannot be named for legal reasons, was found guilty in November last year of causing or allowing the baby's death.
The boy's mother pleaded guilty to the same charge. They will be sentenced on 21 May for their roles in the death of the little boy, as will their former lodger, 36-year-old Jason Owen.
Baby P was seen by social workers, health care workers and police no fewer than 60 times inside of eight months, yet he had 50 separate injuries, including a broken back, before he was found dead in his bloodied cot on 3 August 2007.
In November, Panorama broadcast What Happened to Baby P? which uncovered details of the failings in child protection in the London borough of Haringey.
In Baby P: The whole truth?, reporter Alison Holt's 10-month-long investigation into Haringey council's handling of Baby P uncovers new details about what happened while he was on the child protection register.
The programme includes details of a video of his mother shot by a social worker as part of a new therapy being piloted by the borough.
Crucially, the video includes a discussion about a new man in her life and his access to the home.
Social workers say the mother duped them into believing her
The video of Baby P's mother was not revealed by the council, even when the boy's death was being treated by police as a murder investigation.
This story of brutality, neglect and a mother who lied to protect her abusive boyfriend is one of missed opportunities.
Haringey council said its social workers were duped by Baby P's manipulative mother, who gave every appearance of being cooperative while hiding the existence of her new, abusive boyfriend.
But in her first television interview since the little boy's death, Panorama finds that Baby P's grandmother, who cannot be named, told social workers about the boyfriend. But the council says it has no record of this information.
Baby P's grandmother labelled his mother's boyfriend 'violent'
But the Panorama team discovered that social workers were told about the boyfriend by Baby P's mother herself.
In the video filmed as part of a new therapy being trialled by Haringey, a senior social work manager filmed Baby P's mother talking freely about the new man in her life, going so far as to describe a Valentine's Day meal with him. The video was filmed in March 2007, four months before the baby died.
Haringey has now stopped using the therapy, known as Solution Focused Brief Therapy. The council has told Panorama that it was not appropriate in the case of Baby P.
Retired detective John Shatford said it goes without saying that the video should have been given to police after the baby died.
"Of course it should have been handed over, it was entirely relevant."
Andrew Turnell warns that Solution Based Therapy can be dangerous
Haringey council told Panorama that they only found out about the video in February of this year and said its former head of children's services, Sharon Shoesmith, and her deputy, Cecilia Hitchen - both since dismissed - were responsible for handing over any relevant documents and information to investigators.
Mrs Shoesmith has told the BBC that she cannot comment on the videotape.
On the disclosure of documents, she said it was done in line with the advice of a barrister and everything was disclosed - and only those documents that she was advised were subject to Public Interest Immunity were withheld.
Ms Hitchen declined to comment.
The senior social work manager who filmed the video has said she cooperated fully with the police and made a detailed note of the interview in Baby P's electronic file. But no mention was made that it was videotaped.
Secretary of State for Children, Schools and Families, Ed Balls, said he moved quickly to send in Ofsted inspectors to review Haringey's child protections.
A review of national child protection systems by Lord Laming was also requested. Mr Balls points to a task force looking into the pressures facing front line social workers, bolstered inspections and more support for the profession as key initiatives to improve child protection.
"Will it bring back the little boy who died in Haringey? No, I can't do that. But can we try to make sure that we don't repeat that kind of tragedy in the future? Yes, we can."
But Wes Cuell, Director of Children's Services for the NSPCC, told the programme: "If you ask me the question is there any reason at the moment to think that the rate of child deaths is going to be any less in 30 years time than it was 30 years ago? The answer is no."
Panorama: Baby P: The whole truth? - Monday, 4 May on BBC One at 8.30p.m.