A report shows UK police are failing to stop modern slavery

British police are failing to stop modern slavery in the U.K., a report claimed on Tuesday.

Police cannot identify victims nor close slavery cases, the report by Her Majesty's Inspectorate of Constabulary and Fire and Rescue Services said.

Due to failings by the authorities, victims continue to be exposed and perpetrators continue to exploit the vulnerable, it added.

"While modern slavery cases can be complex and require significant manpower, many of the shortcomings in investigating these cases reflect deficiencies in basic policing practice," Wendy Williams, the inspector of constabulary, said.

"We found inconsistent, even ineffective, identification of victims and investigations closed prematurely," she added.

The police inspectorate said a poor level of awareness and understanding of modern slavery lead victims remaining unidentified and in the hands of the criminals.

"As a result, victims were being left unprotected, leaving perpetrators free to continue to exploit people as commodities," Williams added.

The report went onto say that the victims of modern slavery and human trafficking were identified and treated as immigration offenders.

Campaign group Unseen has published testimony of victims of such slavery.

In one case, "Asif" arrived in the U.K. only to find a black-market job. He was "working in various restaurants for little or no pay, sleeping on their floors and working in hazardous conditions, frequently receiving burns and scars, which caused him great mental and physical stress".

"Manisha" from Africa is a 19-year-old female who, upon arrival in the U.K. "spent my days cooking, cleaning and looking after my Auntie's own two children.

"I worked non-stop from 6 a.m. to 1 a.m. each day. I was beaten most days. Once I was hit so hard in the head I had to have stitches."

The challenge of ending this exploitation was described as "considerable" by one senior police officer.

National Police Chiefs' Council lead for modern slavery, Chief Constable Shaun Sawyer said: "The police service is now actively seeking out and uncovering modern slavery.

"Across England and Wales there are currently over 400 active investigations -- an increase of 218 percent from November 2016, 85 percent of which are led by the police," he said.

Kevin Hyland, an independent anti-slavery commissioner, said the number of people living in slavery in the U.K. could be "in the tens of thousands", higher than the current estimate of 13,000.