Tucked behind a busy north London road, the UK’s first “safe space” for child sexual abuse victims is an oasis of calm. Set over two floors, the building is airy and light.

The toxic legacy of child abuse gets minimal attention, yet the problem amounts to a public health challenge, say experts. Although we don’t know exactly how many children in the UK experience sexual abuse as it’s hidden from view, research suggests one in 20 children have been sexually abused, yet many more incidents go undetected, unreported and untreated.

The Lighthouse hopes to help change that. Launched in October 2018, the £8m service provides a space to support young people up to the age of 18, and 18- to 25-year-olds with learning disabilities. When a child or young person discloses sexual abuse, they are often left to navigate the system by themselves and will have to retell the story several times to different professionals. The experience can be traumatic and lengthy, and it leads to few convictions.

In the Lighthouse, however, all the services needed – medical, social care, advocacy, police and therapeutic support – are housed under one roof.

Nine months into a two-year pilot, the centre has the capacity to support 500 young people each year. Available to families in five north London boroughs, the services are provided by the University College London Hospitals (UCLH) trust in partnership with The Tavistock & Portman NHS Foundation Trust, NSPCC, Metropolitan Police, domestic violence charity, Solace, and Camden council, and the centre receives around 35 referrals per month from social care, schools, police and parents. Young people over 13 years can also refer themselves, though the numbers are low.

“We’re nimbler, and much more responsive,” explains Emma Harewood, the Lighthouse’s delivery and service manager , and the mastermind behind the project. While demand for child and adolescent mental health services (Camhs) has increased, the government has cut almost £500m since 2013 from services providing early intervention support. Even if you report sexual abuse, you’re likely to have to wait months for therapy and support.

Yet the Lighthouse can see children in a matter of weeks. This is largely due to its multi-agency approach and funding. More than half (£4.5m) came from the Home Office, while the Mayor’s Office for Policing and Crime, NHS England and the Department for Education also contributed. Additional services are provided by the NSPCC through partnership funding with Morgan Stanley.

Each child’s route through the service will vary. Lucy, 17, was referred by children’s services after finally telling her mum about the long-term rape and sexual assault she’d been subjected to at home by her dad. She met the Lighthouse’s in-house social workers to relay her experience.

'It feels like I'm organising my brain. It was all a mess but I can see things are getting tidied up.' 13-year-old girl

“At the first assessment, we make sure we’ve got the core people in the room and aim to minimise retraumatising the child,” explains Martin Slack, the centre’s social care liaison officer.

Lucy will also meet an advocate, whose job is to guide her; whether it’s help with the court process or support around housing. “When you’ve been violated, your autonomy is compromised,” explains Anna Weedon, one of the first advocates at the Lighthouse. “We give the young person a bit of control back and make sure they’re being heard.”

Next is the interview, which is often the only source of evidence in sexual abuse cases. They are typically led by police officers in settings that are rarely child-friendly. At the Lighthouse, however, young people are interviewed by clinical psychologists, which is “really quite radical,” says Harewood.

It follows a model known as Barnahus (child house), pioneered in Iceland 20 years ago and then launched in Sweden, Norway, Greenland and Denmark. The system is recognised as international best practice because it’s child-centric and achieves the most effective results.

In Iceland, the change has been startling. The number of convictions doubled between 1995-97 and 2011-13, and the system is proven to reduce children’s trauma and gather better evidence from interviews for court.

In the UK, the Lighthouse has taken elements of the model such as the psychology-led interview. The discussion is filmed by discreet cameras, and watched by the police officer leading the investigation from a connecting room. To get the best interview, the psychologist will ask open, non-leading questions. They’ll also say things like: “Remember, I wasn’t there” to signal to the child that they – not the adult – are the expert here.

The Lighthouse’s service manager Emma Harewood and clinical psychologist Anna Churcher-Clarke. Photograph: Sarah Lee/The Guardian

“You’re having to ask questions that can feel difficult, but if you don’t ask them the defence will,” explains Anna Churcher Clarke, a clinical psychologist at the Lighthouse. “If there were other adults in the house, for example, and the child is saying they didn’t want the abuse to happen, you might ask: You didn’t leave the room at that point, why was that? It can feel like you’re asking questions which imply ‘I don’t believe you’ while letting the child know that you’re with them.”

The final steps include medical and therapy support to help young people recover fully. Although still in the early stages, the feedback from children has been promising. “It feels like I’m organising my brain,” said one 13-year-old girl after her 10th therapy session. “It was all a mess, but I can see things are getting tidied up.”

Before the Lighthouse opened its doors, four child sexual abuse hubs and a children’s haven operated across north London, which brought together agencies and practitioners once a week on existing health premises.

Since the five-day-a-week safe space launched, referrals have shot up, from 80 to 264 cases a year, with an expected 425 by year-end.

Based on the pilot’s success, Harewood hopes more centres will open. “There’s a lot of interest nationally – we’ve had inquiries from Scotland, Wales and Northern Ireland,” she says.

The Home Office has not ruled out the possibility of similar centres being set up. In a statement, a spokeswoman said: “This government is committed to doing all it can to tackle child sexual abuse. We hope the project will lead to improved health and wellbeing and criminal justice outcomes for victims of child sexual abuse.”

In terms of future funding, there’s no “magic solution”, says Harewood. The Lighthouse is fully supported by the government, but is not a statutory service as the Barnahus are in Iceland and Scandinavia. Still, it’s hard to ignore the maths. Child sexual abuse is estimated to cost the UK £3.2bn a year – it can be associated with eating disorders, self-harm, addiction to alcohol or drugs, PTSD, depression and suicide. In the US, for every dollar spent on child advocacy, research shows a further three are saved.

Harewood is well aware of the cost-saving benefits, but for her it’s about more than that. “I’ve met a lot of adult survivors still struggling with significant mental health problems who say to me: ‘if only someone had listened when I was young,’” she says.

“I realised we can change people’s life course. If you can support a child so they don’t feel worthless, guilty or vulnerable, you can protect them from future abuse. You’re breaking the cycle – and that’s so important.”