UK's 'Murky Detention Estate' Exposed: 120 Kids Imprisoned Unlawfully

"There can be no keener revelation of a society's soul than the way in which it treats its children," Nelson Mandela once said.

In 2010, the UK government pledged to end the detention of children for immigration purposes. The same year the Home Office paid $1.6 million (£1 million) plus an additional £1 million in costs for a case involving 40 asylum seekers who had been wrongly detained as adults.

The case involved girls and boys from Sri Lanka, Afghanistan, Iran, Nigeria, Eritrea, Uganda, Somalia and China. The youngest was a girl from Sri Lanka. Many of the girls were survivors of rape and sexual violence.

So far this year, the Refugee Council has secured the release of 17 young people held in immigration detention centers in the UK.

"Unaccompanied children are among the most vulnerable children in Britain. They have often witnessed horrors most grown-ups would struggle to imagine and they arrive here all alone and extremely traumatized", said Refugee Council Policy Manager, Judith Dennis.

"These are children who desperately need our protection, yet their safety is being unacceptably jeopardized by the authorities. It's clear that the stakes are far-far too high for children to be arbitrarily thrown behind bars with adults on the basis of guesswork."

The Bureau of Investigative Journalism has also found that UK border and asylum officers are sending children as young as 14 straight to adult detention centers. Five children have been found to be in Yarl's Wood immigration center since the beginning of 2015. Yarl's Wood remains at the centre of many scandals involving the treatment of detainees by staff — with numerous calls for it to be immediately shut down.

Revelations that children seeking asylum in Britain are being held in adult detention centers also exposes the flaws in decisions made by UK border and asylum officers, who are sending teenagers as young as 14 into detention, without referring their cases to social services.

The Bureau found that:

"Scores of children are slipping through the net to be mistakenly assessed as adults by Home Office staff and then left for months in conditions that many have described as 'distressing' and 'scary'. Lawyers believe these numbers are merely the tip of the iceberg."

Rauf, (not his real name) fled Syria when he was 15 and was smuggled to the UK. Rauf was found by police and taken to the Harmondsworth detention center, near Heathrow. He told immigration officials he was 15, but they did not believe him.

"I was held in a room with several adults and I was scared to go to sleep," Rauf said.

The Refugee Council's Children Section managed to get Rauf removed following two weeks of assessments by social services — his age finally accepted.

"There are no words to describe the horror of detention: it was a prison. I don't know how someone can decide your age in ten minutes."

From "Britain's murky immigration detention estate" to the "black hole at the heart of British Justice" — the UK is the only country in Europe to allow the indefinite detention of migrants. Recent Home Office figures reveal that 30,000 migrants are detained indefinitely — having never committed a crime.

Thousands are held under the Detained Fast Track (DFT) program, a system that has recently been judged unlawful by the High Court in London — but will continue to operate because it would be "inconvenient" otherwise.

Judith Dennis from the Refugee Council is calling on the government to "immediately take steps to ensure that its immigration policies don't put children at further risk: children's safety must always come first."

In 2013, 203 children were held in British immigration detention centers and 155 of them were younger than 11 years old.