A judge has taken the extraordinary step of naming social workers who took part in an attempted “cover up” to keep five children from living with their parents.

One social worker’s report was rewritten by a colleague and a manager to present the parents in a poorer light, Judge Mark Horton found. He also accused social workers of lying under oath.

In an scathing ruling, the judge condemned the conduct of social workers at Hampshire County Council involved in the case, which related to five Portsmouth siblings aged between three and 16 in foster care.

He said: “It is exceptional to find a case in which there has been deliberate and calculated alteration of a report prepared by one social worker in order to make that assessment seem less favourable, by another social worker and the team manager; the withholding of the original report when it was ordered to be disclosed and the parties to the alterations lying on oath one of them twice, in order to try to cover up the existence of the original report.”

The judge added: “I certainly have not previously come across [a case] quite like it either at the Bar or as a judge.”

The children were originally taken into care because of concerns about the way they were being looked after by their parents.

The inability of the parents “to set consistent boundaries had led to appalling neglect of the older children’s educational, emotional and social development and neglect of all of the children’s health needs,” the judge accepted.

But he added that at one stage the children had been illegally removed from their parents’ care, and a “fair parenting assessment” had not been done.

The judge said that the “enormity” of what had been done by the council officials led him to name individuals who still work as social workers so that others are aware of “their shortcomings.”

Social worker Sarah Walker Smart had “lied twice to me on oath,” said the judge in his ruling.

Her former manager, Kim Goode, now district manager for the Isle of Wight, “was the person who initiated the wholesale alteration of the original report and who attempted to keep the truth from the parties and me.”

The judge also found that evidence given by Lisa Humphreys, Ms Goode’s former manager, now assistant director of children’s social care at Lambeth Borough Council, was “deeply unimpressive.”

Judge Horton added: “She made a ‘hollow’ apology to the parents during her evidence; she regarded a social worker lying on oath as ‘foolish’ and she failed to accept any personal responsibility for what had gone on under her management.”

He registered his concern that the social workers “had not apparently been subject to disciplinary proceedings” and directed that his judgement be sent to Ofsted to them consider whether further action is required.

But although the judge found that “the parents love their children and the children love them” with “deep and positive emotional relationships” within the family, he concluded that the three boys and two girls should stay in fostering care.

In a statement yesterday, a spokesperson for Hampshire County Council, said: “There are some aspects of the Court’s criticism that we believe are not quite correct however, and are considering our position in this regard. We do accept that there were deficiencies in some of the social worker practice in this case and subsequent action was taken. We are satisfied that at no stage did any of the named officers deliberately mislead the courts.”

A spokesperson for Lambeth council, where Ms Humphreys works, said: “I can confirm that she is employed at Lambeth council, and that we are aware of the case.”