Mr Justice Francis, who is based in the Family Division of the High Court in London, said the boy had been embroiled in care proceedings.
The judge said he had concluded the youngster should live with a grandmother who had cared for for him for most of his life.
He hinted his decision about the boy's future might have been different if social services staff had acted properly.
The judge said social workers had raised concerns when the little boy was a baby.
Staff had moved him from home and placed him in the care of his grandmother in August 2013.
However, Mr Justice Francis said the legality of that placement was in "serious doubt".
He said nearly two-and-a-half years had passed before bosses began family court litigation and asked a judge to oversee the boy's case.
During that time, 10 different social workers had been involved; and the parents of the boy had split up with the father living in Doncaster and the mother in Northampton.
Mr Justice Francis said staff at Northampton County Council, where the family were living at the time, had failed to carry out "full and adequate" family assessments and failed to carry out adequate care planning.
The judge said there had been "extraordinary delay and dereliction of duty".
"I find the local authority to have been in egregious breach of its duties," he said.
"Only speculation, which is of course always to be avoided, could fuel consideration of what orders the court might have made had proper and timely steps been taken by this local authority in relation to (the boy's) welfare."
He added: "I do ... encourage the local authority in the strongest possible terms to enter into sensible negotiations forthwith to resolve the damages claims of the adults in this case."
The judge said he would make decisions of the size of damages awards if agreement could not be reached.
He said council bosses would be able put their side of the story through lawyers.
Mr Justice Francis has not identified the family involved in his ruling.
Mr Justice Francis says bosses at Northamptonshire County Council have not fulfilled their duties towards the youngster or his parents.
The parents of the boy, who have not been identified, separated following
He has concluded bosses have breached rights to a fair trial and respect for family life, and complained of a "catalogue of failures and delays and incompetencies".
The judge said the parents had taken legal action claiming their human rights had been breached.
He urged council lawyers to negotiate settlements of their damages claims.
Detail of the case has emerged in a ruling by the judge following a hearing at a family court in Birmingham.