Imagine you’re a single mother. You get injured in a car accident, and a kind friend offers to look after your two young boys while you’re in hospital. You accept with relief. Three weeks later, when you get home, you’re still a bit shaky, so your friend suggests it might be best if she has the boys for another few days. You are unsure, but she is persuasive. First thing on Friday you send a text saying you will pick them up from school. A few hours later – you’ve been awaiting her reply, slightly puzzled at the delay – a text pings back: they are really looking forward to the fun weekend she has planned. How about revisiting the situation on Monday?

With mounting unease and some anger you race over and tell her the kids are coming home with you. You are met with a smiling refusal. Until she feels that you are well enough, she explains calmly, they are staying with her. Then she bundles them into her car and heads off to a holiday camp. Presumably at this point you would call the police. Given that there are laws in this country about kidnap, you would get your children back pronto, and your “friend” would be in serious trouble.

Kidnap is not a crime typically associated with Britain. But it is happening, right now, and the local authorities involved don’t want you to know. High court judge Mr Justice Keehan, in a scathing judgment earlier this year at Nottingham family court, revealed that at least 16 children have been “wrongly and abusively” looked after by Herefordshire council, under something called a section 20 arrangement, for “wholly inappropriate” periods of time. For one boy, that was the first nine years of his life after he was born to his 14-year-old mother. For another boy it was eight years, from the age of eight to 16, despite his mother on several occasions withdrawing her consent. Shockingly, at the time of the judgment, 14 children were still being wrongfully looked after by Herefordshire on section 20 arrangements, despite the local authority knowing full well the judge’s displeasure.

These are not court orders. They must be a voluntary agreement, and in legal terms they precisely mirror the situation where the single parent consented (at first) to her friend looking after her boys. For a section 20 to be legal, social workers must be certain they have a parent’s informed consent to their child being accommodated by the state. And a parent can withdraw consent at any time, because they keep full parental responsibility. If Mum or Dad wants to turn up at a foster carer’s house at midnight without notice and take their child home, they can. No ifs, no buts. But many parents say social workers threaten that if they do, it will mean a trip to court for a care order. There is no surer way to scare the living daylights out of a parent. And so frightened acquiescence – not the same as consent – tends to be the result.

The sheer scale of the section 20 abuses revealed in Keehan’s judgment dwarfs many other egregious instances of its misuse that have been detailed in a slew of judgments published by outraged judges over the past few years. Given the substantial publicity these judicial criticismshave had in the social work and legal press, it is difficult to see how social workers in good faith can plead ignorance of the law. The only alternative is that they are recklessly, even deliberately, choosing to flout it. Despite the fact that one boy’s mother withdrew her consent to section 20 accommodation, Herefordshire’s children’s services deliberately chose not to follow the council’s legal officers’ repeated advice that a care order should be sought if it was thought the boy should remain in foster care.

In the case of the boy who was on a section 20 for the first nine years of his life, the judge observed that repeated recommendations made by his independent reviewing officer that his case should be brought before a court were ignored by those above her. Added to this miserable litany of failure, Herefordshire council also accepted that it had “not respected” his 14-year-old mother’s human rights as a vulnerable child herself: it’s doubtful, at the age she gave birth, whether she could have given informed consent. Grasping this surely shouldn’t require a forensic understanding of children’s rights: basic common sense would do.

The poet Lemn Sissay recently agreed to accept a compensation package from Wigan council for the abuses he suffered as a child while in its care. Despite his mother writing letters begging the council to return her baby once she was better able to look after him, he would not be reunited with her until he was in his late 20s. That was years ago, but abuses of power are still continuing today.

Social workers must stop acting as if they are above the law. In reporting on family cases, I have observed the most extraordinary sense of entitlement and arrogance both in court hearings and in email communications when attempting to investigate and highlight poor and unlawful practice. There is no humility. There is instead a knee-jerk opposition to anyone presuming to want to hold a local authority publicly to account. Given that family cases are heard in private, if the judge had not rejected the council’s plea to keep its identity secret, nobody would ever have known about the longstanding and outrageous failings of Herefordshire’s social work team. Why, just because the state is the “corporate parent”, should it usually get a free pass on scrutiny and accountability?

Kidnapping children is wrong, whoever does it. When it is the state, which then argues for its transgressions to remain secret in the family courts, it is terrifying. There are growing calls for these courts to lose the privilege of privacy that child protection professionals have benefited from for so long – because how many more human rights abuses are being hidden from view when judges opt not to publish judgments, and when journalists who go to family courts are not allowed report what they see?

• Louise Tickle is a freelance journalist who writes on education, social affairs and family law