A man who rented hundreds of properties that he sub-let to criminal gangs running brothels and cannabis farms has been jailed for seven years and four months.
Chinese national Feng Xu used several fake identities to secure accommodation, according to the National Crime Agency (NCA).
Feng was arrested in Birmingham in May as part of a major investigation into modern slavery and human trafficking.
He had previously admitted 22 fraud, false identity and money laundering offences at Birmingham Crown Court.
The 43-year-old was described by investigarors as a "prolific operator" and an "important enabler" for different criminal networks involved in prostitution, drug production and housing illegal immigrants.
Feng, who ran his network for more than three years at his home in Birmingham, paid out more than £4m in rent.
One computer database listed 446 different addresses that Feng had been involved in renting, investigators said.
Matt Rivers, branch commander at the NCA, commented: "Using numerous false identities and false documentation he was able to supply hundreds of different properties across the UK.
“We believe that taking him out will have caused significant disruption to a number of different organised crime groups involved in sex trafficking and drug production."
Feng, who has lived in the UK illegally for almost 20 years, will face deportation after serving his sentence.