A series of coordinated overnight raids by U.K. immigration officers led to the arrest of 11 people believed to be part of a sophisticated Europe-wide human smuggling ring.

Police smashed down doors and swept through five addresses across England earlier this week. At the same time, more than a dozen arrests were made in Belgium and Bulgaria.

The operation, codenamed Halifax, revealed further evidence of the booming European human trafficking trade -- a lucrative business that puts scores of desperate people on a path to black market labour and sexual exploitation.

The number of people reported to be victims of slavery and human trafficking surged nearly 120 per cent between 2013 and 2016, according to figures released by the U.K. National Crime Agency.

“We’re targeting the organizers of a people smuggling network, and we are going to be searching for evidence and arresting subjects. That will feed into the wider pan-European investigation,” Inspector Andy Ratcliffe said before a raid in Gateshead, U.K.

Modified vans seized by authorities show the brutal tactics criminals employ to conceal human cargo. Secret compartments in front of the rear doors look impossibly narrow. Photographs reveal how they are used to transport entire families, some willing to shell out as much as $15,000 per person.

“Normally, you don’t even keep animals like this,” said one investigator.

The network is alleged to have transported migrants from Afghanistan to the U.K. Authorities also believe they are linked to a string of fatal smuggling attempts across the European continent.

In one 2015 case, the bodies of 71 migrants, including children, were found crammed inside a truck abandoned at the side of an Austrian highway.

Four men are on trial in Hungary in connection to the deaths. They are said to have ignored the cries and pleas of the occupants as they slowly suffocated.

U.K Immigration Enforcement director of Crime and Financial Investigation Steve Dann said those who survive the journey do not typically thrive once they arrive at their destination.

“The people who they are trafficking end up being exploited and could end up in labour exploitation, sexual exploitation, and the black market,” he said. “This is really about trying to prevent that activity taking place and trying to save lives.”

With a report from CTV’s Daniele Hamamdjian in London