Roman Feko and Ladislav Fedak jailed for exploiting victims
An undercover investigation by BBC Wales Investigates has shown the extent and scale of labour exploitation and modern day slavery in the UK.
With a 300% rise in recorded slavery victims since 2012, officials acknowledge there is a growing problem.
In the programme entitled People for sale - broadcast Monday at 20:30 BST on BBC One Wales - we filmed inside a Czech court for the conviction of two men, Roman Feko and Ladislav Fedak.
The brothers in law ran cleaning companies in Cardiff and were recently jailed for exploiting four victims who had come to Wales in search of a better life but ended up being treated like slaves.