Campaigners have called on the Home Office to urgently investigate what has happened to the hundreds of victims who have gone missing. Photograph: Anna Gowthorpe/PA

Home Office data shows 566 people were categorised as missing between 2020 and 2022

Hundreds of trafficking victims in the UK have gone missing after being referred to the government’s scheme to protect them, the Guardian has learned.

The news comes after the immigration minister, Robert Jenrick, admitted in January that since 2021 about 200 child asylum seekers had gone missing from hotels where they had been in the care of the Home Office and its contractors.

The Guardian has obtained freedom of information data from the Home Office which reveals that 566 potential or confirmed victims of trafficking – from the UK and other countries – were categorised as “missing” between 2020 and 2022 after being referred to the national referral mechanism (NRM), which is designed to provide victims with safety and support.

The highest number was 258 victims in 2022, up from 232 in 2021 and 76 in 2020. The majority of the children who went missing were Albanian boys, and the majority of missing adults were Vietnamese men.

Organisations advocating for trafficking victims expressed concerns about the data. Maya Esslemont, the director of After Exploitation, called on the Home Office to urgently investigate what happened to the hundreds of victims who had gone missing.

“It is incredibly worrying that such significant numbers of victims are slipping through systems of support,” she said. “This data shows a real risk of retrafficking in the UK, even amongst people who report modern slavery and make steps towards recovery.

“The role of control in modern slavery cannot be overstated, and many victims will fear repercussions from their traffickers for many months or years after exploitation as they are afraid of harm to themselves or loved ones if they do not remain in contact with their traffickers.

“The government must urgently investigate these cases in order to understand what factors left survivors vulnerable to falling out of the process. It is vital that the NRM itself is fully funded and that every single survivor who needs safe housing, psychological and financial support to avoid retrafficking is able to access it.”

Kathy Betteridge, the director of anti-trafficking and modern slavery for the Salvation Army, which has a contract with the Home Office to look after victims of trafficking, said: “Criminal gangs use a range of techniques to trap people into modern slavery, which include violence and threats to the victim’s family. Of course our support workers explain the reality of how safe survivors are in our support service but we can’t guarantee their families’ safety, and for some people the fear is too strong.

“Sadly, most of the people who abscond are Vietnamese nationals and this seems to be linked to the extreme levels of psychological abuse that they are subjected to by their traffickers. When they arrive at our services they are especially wary of the authorities and worried about threats to their families.”

She added: “We are seeing some success with pilots of safe houses specifically for Vietnamese men, where we’ve found they respond well and settle better.”

Charities recently warned that modern slavery survivors could be left at risk of retrafficking within the UK owing to a lack of resources to support them.

Home Office sources said the numbers missing amounted to only a small percentage of the 35,827 people referred to the NRM over this period.

A Home Office spokesperson said: “We are committed to do everything we can in supporting genuine victims of modern slavery. Individuals who we consider to be potential victims of modern slavery are provided with appropriate support, including accommodation. There are many reasons people may leave accommodation provided for them, and it is testament to the world-leading support the UK provides that so few of those placed in that accommodation do so.”