Two years later, 500 Vietnamese construction workers were allegedly found last month working in conditions of forced labour with their passports confiscated and living in cramped and degrading conditions.

The allegations have shocked Serbians with the European parliament demanding an investigation into to how a major case of human trafficking could have apparently been allowed to fester in the heart of Europe.

Yet Linglong factory was only the first stop in a much longer journey towards the UK and Europe for many of the workers found at the factory.

An Observer investigation has found that Serbia and Romania are being used as new gateways to Europe for smuggling and trafficking gangs who are using guest worker visa programmes to transport large numbers of Vietnamese workers into eastern Europe. There they are often exploited in factories and construction sites before some are transported across land borders into the EU and, eventually, to the UK.

Read more...