In Wednesday’s final episode of Josh Baker’s gripping documentary about Shamima Begum, he visits a camp where the young woman from east London was once held. They call it the “mini-caliphate” because scores of children, radicalised by their mothers, hurl rocks at whomever they perceive as the infidel. A kid of about eight years old says he wants to decapitate Baker; another, who is about five, approaches with something sharp that he perhaps wants to use as a weapon, but is disarmed when the journalist smiles at him and shows him his camera. It’s a bit ham-fisted for my tastes: I don’t need a parable to understand that a five-year-old can’t be held responsible for his own radicalism, nor that he could be won round with kindness. I’ve met five-year-olds. It is bizarre to me and dangerous for many citizens of the UK that none of the supreme court or Special Immigration Appeals Commission appear to have met any 15-year-olds. Begum’s appeal was rejected last month, when the commission decided that although there was “credible suspicion” that Begum was trafficked for sexual exploitation, the decision to remove her citizenship was ultimately one for the home secretary, and the evidence was “insufficient” for them to deem the decision unlawful. The idea that she poses an unmanageable risk to national security is fanciful on many counts, not just because she has now resiled from Islamic State ideology altogether and, on all available evidence, wasn’t even much of a danger when she was still embroiled. She was just a subjugated child bride, living in Syria with almost no contacts outside her home, trying and failing to prevent her first two children from dying of disease or malnutrition. Even if we were to accept that her repentance is fake and her zeal for the caliphate as strong as ever, that would still mean accepting that the assembled forces of British security and its penal system were no match for her. And if we accepted that, we’d have to consider it much safer for this lifelong fundamentalist warrior to live in Syria, unmonitored by security services, than in the UK at her Majesty’s pleasure. On the matter of the suspicion of trafficking, going by the reporting in the BBC’s podcast, from her journey once she reached Raqqa – from a women’s hostel kept deliberately squalid so that its residents would seek a husband as soon as possible, into a marriage to the Dutch IS fighter Yago Riedijk – it seems clear that its purpose was sexual exploitation. She was deceived into this journey, with the collusion of a Canadian spy and the wilful incompetence of the British police. Before Begum and her two friends Amira Abase and Kadiza Sultana even left London, the police wanted to interview them in connection with the disappearance of a fourth girl, Sharmeena Begum (no relation, but a schoolfriend), who had gone to Syria and was trying to persuade them to join her. So the police wrote to the parents of the Bethnal Green three, asking permission to interview them, but handed the letters to the girls themselves, who did not pass them on, obviously. They were teenagers who were being groomed and indoctrinated online; this everyday act of dissemblance was not beyond their wit, and if the police had approached it as a safeguarding issue rather than one of intelligence gathering, the girls would probably still be in London now. Instead, it is thought that Kadiza died in an airstrike and Amira died in circumstances so horrific that I warn you not to listen to the last episode of the podcast while you’re out, if you don’t want to start crying in public. Taken in the round – the way they were groomed and gulled by IS agents, the way they were failed by security services – these girls did not have the protection that any citizen of the UK deserves, and there is no crime so heinous they could have committed that would exculpate the state for that failure. The most seismic message of this judgment, however, is on statelessness. Deprivation orders, once vanishingly rare, have been used with increasing frequency by the Conservatives, peaking at 104 in 2017. They can be issued on one of two grounds: fraud or the baggier “conducive to the public good”. Figures are only intermittently released, so the real number of people in Begum’s position, since 2019, is not known. Look, there’s no gilding this: if you are British-born but have the possibility of a dual nationality as a second-generation immigrant, you do not have the same rights as, say, I do. So we’re operating under a two-tier system of rights, based on nationality, which is to say that the fundamental principle that we are all equal in the eyes of the law has been repudiated. We should all take this deadly seriously. Who knows whether the removal of violent protesters may one day be considered “conducive to the public good”? The documentary took some flak for giving Begum a “platform”, the logic being that she was so evil she didn’t deserve it. This is a childish position, and Baker and his team were right to defy it. I would criticise it from the other direction: that it drills so hard into Begum’s motivation that it misses the critical point – which is that you can’t ask a trafficked 15-year-old, even in retrospect when they’re older (she’s now all of 23), what their “motivation” was. But I have to concede that the result is rigorous and humane, and it has raised some vital questions that society has a duty to start answering. Zoe Williams is a Guardian columnist