London, October 12 (RHC)-- An investigation into the situation of migrants whose asylum applications are being reviewed in the UK suggests that British authorities detain them unlawfully and for indefinite periods of time.

The Guardian newspaper published the results of its investigative report into the situation of some 8 percent of migrants held in the United Kingdom, saying many of those people were being tortured or abused in detention centers across the country.

The report said more than half of those surveyed, around 200 migrants held in seven deportation centers in England as of 31 August, were identified as an “adult at risk.”  It said most of the individuals were held without a clear reason and in breach of the Home Office (interior ministry) guidelines saying migrants should be incarcerated in extreme cases.

The report, which was conducted in cooperation with 11 law firms and charities that work with those facing deportation, said more than 80 percent of the respondents to the survey were under an open-ended detention as they did not know when they would be released.

The study showed that UK authorities imprison the migrants for an average four-month period although half of those incarcerated had not committed a crime.

A third of those migrant detainees had dependent children in the UK, a majority had lived in the UK for five years or more and some had been in the country for more than 20 years, said the survey.

According to the Home Office figures, some 2,500 asylum seekers are under detention in the UK. A spokesperson of the ministry defended the detentions as “an important part of the immigration system” although acknowledging that further improvements could still be made to the system which the official said must be “fair, dignified and protect the most vulnerable”.

The study showed that each year roughly half of the total number of detained migrants are eventually released back into British society, rather than being deported with many taking future legal action over their treatment.

Commenting on the Guardian’s report, Roland Adjovi, a representative of the UN Office of the Human Rights Commissioner’s arbitrary detention working group, said that detention "is truly a measure of last resort."

“Detention in the context of migration must be a measure of last resort. Such detention can never be of unlimited duration, and the national legislation must clearly prescribe the maximum permitted duration of detention,” said Adjovi.

Diane Abbott MP and member of the Shadow Cabinet said the report showed Britain’s detention of migrants was “a scandalously inhumane and unjustifiable system” while responding to the study and the ongoing controversial treatment of migrants.

“There have been repeated assurances that vulnerable people, victims of trafficking and children would not been detained. But this investigation shows that those assurances are worthless. People are even being detained even though there is no instruction for their removal,” said Abbott.

Despite living in some of the worst conditions, immigration detention centers are often run by companies which have been given contracts by the Home Office, but which have a track record of cutting corners when it comes to ensuring the safety and well-being of vulnerable migrants.

Previous studies have indicated that women and children are often some of the most affected by increasingly substandard conditions in immigrant detention facilities.