A teenage boy with special needs has been "failed" by a Canvey specialist care unit, a judge has said.

The boy, who cannot be named for legal reasons, was placed at Island Lodge, on the island, which specialises in helping children with complex care needs.

However, Judge Kate Purkiss has criticised managers at Barking and Dagenham Council for their failure to monitor the care the teenager was given at the specialist unit and she said his parents were treated in an "appalling way" by some professionals.

The boy had been placed in a unit which "manifestly" failed to meet his needs and had suffered "significant harm", the judge said.

His parents had raised concerns but they had been ignored, she said.

She said "every aspect" of a system which should have resulted in "positive decision-making" appeared to have failed.

The judge has aired her criticisms in a written ruling after analysing the boy's case at a private hearing at the East London Family Court in Canary Wharf, London, earlier this year.

Island Lodge staff had not been trained to look after a child with the teenager's disabilities, did not know how to communicate with him and had exercised "unnecessary and probably unlawful restraint", the judge said.

She said bosses at Island Lodge had written to the council indicating that they did not agree with some of her findings.

Judge Purkiss said the boy's parents had asked the council for help because they were having difficulties managing his behaviour.

They had agreed to him going into council care and being placed at Island Lodge.

The judge ruled that he should stay in council care but move to another unit.

"Island Lodge was never the right place for (the boy)," said Judge Purkiss.

"Staff at the unit did not know how to communicate with (him) and were hyper vigilant he would become aggressive.

"This led them to exercise unnecessary and probably unlawful restraint."

She added: "Every aspect of the system which should have resulted in positive decision making by professionals for (the boy) appears to have failed.

"The local authority, however it characterises the failings of Island Lodge now, secured a placement for (the boy) which manifestly, and from the outset, failed to meet his needs and keep him safe and then ignored his parents' concerns.

"It failed adequately to monitor the care which was being provided to (him)."

The judge went on: "This has resulted in (him) suffering significant harm."

She said the boy's parents had been "marginalised" and treated in an "appalling way" by some professionals.