A High Court judge heavily criticised Haringey Council after social workers failed to tell the father of two boys that their mother was in a relationship with a convicted child sex offender.

Mr Justice Hayden said there had been a “root and branch failure of social work” and the team “lost sight of the most basic of child protection and safeguarding procedures” in a verdict handed down on May 11.

He described the “litany of failure” as “profoundly troubling” and said it signalled a need for “significant retraining”.

A lawyer for the council told the judge social services managers had a “real concern” about what had happened and there was a “determination that there should be a full investigation”.

The mother became involved with a man convicted of child sex offences after separating from the boys’ father. One of the boys is disabled.

Despite the council being told of the relationship via an anonymous phone call, social workers twice failed to tell the boys’ father of the sex offender’s involvement in their lives – which the judge said “defies comprehension”.

In a written ruling following private hearings, Mr Justice Hayden said: “It is not only a breakdown in understanding of the fundamental principles of child protection, it is active discrimination towards a father.”

The judge said the local authority “failed, in the initial stages, fully to appreciate the significance of the risk” posed by the sex offender.

Mr Justice Hayden added social services “failed in any way adequately to assess the information that was at their disposal, or easily attainable, in order to conduct a professional risk assessment”.

According to the judge, the boys’ father had become frustrated over the council’s “delays and shortcomings”. His “irritations” were expressed to council staff in email correspondence, and the judge said some of his behaviour was not justified.

At one point, social services “declined to speak or meet with the father”.

The judge said: “I am not convinced that was a proportionate response or a sensible one.

“It created difficulties of a different kind and contributed, in due course, to the local authority making some fundamental errors in which they fell considerably short of their obligations to safeguard and protect the children subject to these proceedings.”

The council’s lawyer said the deficiencies identified in this team “are not representative of practice in this local authority’s children’s services more generally”, with the judge commenting: “I profoundly hope that is correct”.

The council was not identified in the judge’s original ruling. After the decision was contested, the local authority was named on Wednesday (May 20).

Haringey Council has previously faced criticism over the deaths of Peter Connelly – known as Baby P – in 2007 and Victoria Climbie in 2000.

Opposition spokesperson for children and families Cllr Tammy Palmer (Lib Dem) said: “It’s appalling that such severe failings from a local authority should happen anywhere, but this is especially alarming in a borough with such a catastrophic history of failing to protect our most vulnerable children.

“Haringey’s residents need urgent answers from the senior leaders of this council about what went wrong and whether this is a one-off or indicative of a systemic failure.

“In order to rebuild trust and confidence in the light of these damning findings, any investigation or inquiry must be prompt and it must be public.”

Cllr Zena Brabazon, cabinet member for children and families, said: “The most important thing for me to note is that the children remain safe, and their wellbeing is our primary focus.

“The assessment and management of the risks to the children was completely unacceptable and fell far below the council’s usual social work practice. We recognise wholeheartedly that this judgment highlights areas where we can and must improve – many steps have already been taken and significant progress has been made.

“We firmly believe that this judgment is not a reflection of our wider practice in children’s social care. Since the Ofsted inspection of 2018 we have made significant changes, and Haringey has been commended by Ofsted and its partners for its work strengthening and improving its children’s services.

“We have been carrying out our own review into what can be done better, and this will continue, along with a new, independent assessment. We have brought in additional resource and training and are accessing expertise from some of the best services in the country. We have made real progress, but where there are still improvements to be made, we will continue to make them.

“It is our duty to protect our young people. We did not do well enough in this case, and that is being rectified now, and going forward.”