Most of the women and children have been detained in Al-Hol and Al-Roj camps, run by Syrian-Kurdish authorities, along with thousands of other civilians, since the fall of the Islamic State group.
The report claims that UK intelligence officers regularly enters the camps to identify British women and children in order to withdraw their nationality from them, The Guardian reported.
The report reveals that conditions inside the camps are "fundamentally unsafe" and the "cruel, inhumane and degrading treatment" of residents are commonplace, amounting to serious breaches of their human rights.
The Rights and Security International charity describes the two camps as Europe's "equivalent to Guantanamo".
"The camps in which they are being held are fundamentally unsafe environments in which physical violence is common, the conditions are barbaric, and psychological trauma is rife," the report states.
Children living in the camps have fallen victim - often with fatal consequences - to malnutrition, dehydration and hypothermia, along with periodic fights and fires.
The report says that 25 residents die every month in Al-Hol camp.
Children aged-over 10 have been forcibly removed from their mothers, women placed in solitary confinement, while detainees have been shot and sexually abused, the report claims.
The rights group said that the horrific conditions inside the two camps could even pose a potential security threat, if not dealt with immediately.
"This is Europe's Guantánamo, but for children. It beggars belief that the UK, who rightly condemned the abuses of Guantánamo Bay, now stand by and let children, including a newborn British baby, die. Now these women and children face another brutal winter with more deaths," Yasmine Ahmed, the executive director of Rights and Security International, said according to The Guardian.
"The claim that it is safer to leave women and children in the camps flies in the face of security experts who say that the real security risk comes from leaving these women and children in the detention camps where they are vulnerable to radicalisation, and where their dire conditions can serve as a recruitment tool."
Richard Barrett, a former MI6 director of global counter-terrorism, echoed these claims.
"The longer they stay without proper assessment of their mental and physical health or their attitudes towards their families, communities and countries - the more unpredictable they will become. And the more difficult it will be to determine what they're going to do," Barrett said.
The report went on to claim that the UK was removing citizenship from the women and children "in a far more systematic way" than other European countries, who also have citizens in the camp.
A UK government spokesperson said that withdrawing citizenship is not a decision it takes likely but its priority is "to ensure the safety and security of the UK".
"We have also made it clear that we are willing to repatriate orphans and unaccompanied British children from Syria where this is feasible and there is no risk to UK national security. Every request for consular assistance is considered on a case by case basis," the spokesperson said.
"The UK is at the forefront of the humanitarian response in Syria, contributing more than £3bn and funding life-saving supplies such as food, water, healthcare and shelter, including in IDP camps in north east Syria."