When Professor Dame Carolyn Hamilton was a pupil at South Hampstead high school in the 1960s, she noticed a peculiar trend. Each year had almost exactly the same number of Jewish children.

“I asked questions of the teachers, who were very uncomfortable and I never got a straight answer, but quite clearly there was a quota,” she recalls. “That’s what first raised my interest in human rights issues — the unspoken, surprising discrimination and the realisation you are the subject of it. It was quite shocking — it was so blatant in that school setting.”

Such practices have thankfully been confined to the past, but Hamilton has held on to her determination to right wrongs wherever she sees them. A lawyer and something of a trailblazer, today she is an internationally respected expert on child protection and juvenile justice, having worked as a consultant for Unicef and other agencies and NGOs in some 25 countries. Her career has seen her work with numerous governments, from supporting the rights of refugees or children in prisons, to helping former child soldiers, children in warzones, or tackling egregious examples of modern day slavery.

She has practiced as a barrister, published widely, and is the director of International Programmes and Research at Coram Children’s Legal Centre. In 2005 she received the Sigrid Rausing Prize for inspirational leadership; four years later the Gandhi Peace Prize for her work with sexually exploited girls in Tajikistan. Last month, Hamilton was at the Palace to be invested as a Dame by Prince William.

The daughter of a German Jew who arrived in Britain on one of the last ships out in 1938, Hamilton’s path came naturally. “My father had been on his own since he was just 15,” she explains. “As I reached that age I remember thinking, what would it be like, with nobody to support you? He thrived but it was very hard. I’ve always been interested in children separated from their families and how they cope.”

After graduating, she took a post teaching family law at the University of Manchester, then moved to the University of Essex, where she began working with NGOs and playing a leading role in developing mediation services.

Tajikistan, in 2001, was her first major overseas consultancy project for Unicef, and she was thrown in at the deep end. Tasked with supporting officials in transforming the child protection and juvenile justice systems — then Soviet-era relics — she encountered an abusive system “that was completely against all understanding of children’s rights”.

“I was wheeled in to a gathering of about 15 government people, and told to lecture them for a week,” she says. Seeing the resentful faces, she took a different tack. “I said let’s instead go out and have a look. I took them to detention places, police stations, temporary isolation centres; we went to special schools, and the prisons. Although they were responsible, they’d never been inside these places, and they were shocked — and they were shocked at how shocked I was. It opened their eyes.”

In the subsequent period, Hamilton worked with those officials to improve things. She waves away credit, saying her role was to empower others, although it’s clear she did much more — and while it was “an immense struggle”, reform did happen. She is particularly proud of a regulation that was pushed through to prevent young female victims of sexual abuse from being kept in administrative detention for years at a time, as was happening until then.

Around then, Hamilton was asked to help the Palestinian Authority redo its child protection system, work curtailed only by the Second Intifada. “Again it was what would you change and how,” she says. Having spent a summer at Hebrew University, and with relatives in Israel, this was an eye-opening experience. “What was interesting about it was seeing the situation from both sides. My conclusion was actually how similar the two societies are and how poorly served by the politicians they are.

“I look at the children on both sides and I think this is very sad because on both sides they are anxious and affected by the conflict. They never know whether they are safe and I don’t think it matters which side you come from,” she says sadly. Her being Jewish never came up, she says, and she got on extremely well with the PA officials involved.

Closer to home, Hamilton has brought a number of cases to the Supreme Court on the right to education, including representing a Muslim girl who wanted to wear a jilbab (a long and loose-fitting coat or garment) to school. The author of a book on family law and religion, she is hungry for an opportunity to challenge unregistered Charedi schools, a matter Ofsted Chief Inspector Amanda Spielman raised in December as a serious problem.

Finding a pupil willing to go up against the Charedi community, before they turn 21, has made a legal challenge difficult thus far, but Hamilton is apoplectic about the prevalence of these schools. “It’s astonishing — these children disappear out of the education system and nobody asks any questions,” she says. “Why do we as a society allow them to carry on? Some of them have been going for 20 years, why do people turn a blind eye? These children are not getting a right to education that would enable them to participate in British society. The Jewish community should be up in arms.”

That aside, she thinks Britain is an increasingly good place for children, although she worries about the demise of programmes like SureStart and would like more support for parents at the early stages. “Sometimes when you are doing care proceedings you see these children, and you think: you don’t and never will have the same chances as a child of mine, because you’ve had such a terrible start.”

Overall, though, she says Britain compares favourably to other countries. “When I look abroad parenting is often really poor and very often violence permeates, not just at home but particularly in schools,” she sighs. “The way they look at children is quite often as chattel.”

A mother (and now grandmother of six), she must have been affected by what she has seen during her career. “It took me a while to separate things,” she admits. “I got very cross to begin with and then I decided really most people wanted to do their best for children, but were frustrated and demoralised by the lack of skill and support.” Going into a home where children were really badly treated, she says she’d have to take the view that staff really wanted to do their best, and focus on equipping them to do it.

As the child of a refugee, Hamilton is heartbroken to see children vulnerable to traffickers as they attempt to reach Britain. But despite her family history, she is cautious about Britain taking in high numbers of unaccompanied child refugees, highlighting the lack of council-funded support for them when they leave care at just 18.

“We don’t want them to be left with no support in Europe or anywhere — on the other hand if we’re too willing to take them, are we helping the traffickers?” she says. “The question is how to support unaccompanied children who are really in danger without encouraging them to try for a new life, because coming as an unaccompanied child is immensely problematic. It was when my father came but even more so now.”

Her father’s experiences — he escaped, but lost all his relatives in the Holocaust — shaped her childhood. “It had a profound effect, listening to stories of loss like that,” she says. In 2016, in what was clearly a painful situation, Hamilton’s brother took her to court over the inheritance from an offshore foundation of their father’s.

Hamilton’s lawyers suggested her brother’s claim amounted to an accusation their father was a tax evader who moved his cash overseas to deceive HMRC. They successfully argued that the money was in fact “an escape fund” placed abroad legally — the court agreed.

Hamilton never doubted her father’s motives. “It’s difficult to explain unless you’ve lived through it, what an impact the Holocaust had on him,” she says. “It never, ever went away. He was very guilty about the fact his sister had died and he’d lived — he felt his father hadn’t done enough, that had he put some money aside he could have got out.”

Receiving her damehood allowed for a brief trip back to London and her Islington home. Hamilton’s husband is partially based in America, while her job involves near-constant travel. Her current work is on violence against children and by children in terms of terrorism. “I’m looking at strategies to prevent it and at what should the legal response be. In some countries it’s very punitive and I don’t think it should be, because in the end you want to address this child’s behaviour and turn them away from violent extremism.”

Fifty years on, the teenager who challenged discrimination shows no sign of slowing down. She says she is still surprised by man’s inhumanity to man, and what people are capable of. But her focus is always on finding a way forward. “It’s what can I do to turn it around. That has guided me in all my work.”