A man who repeatedly conned letting agencies about his ID has been jailed for operating almost 450 rental properties across the UK. The case highlights problems with referencing checking.

The homes, from Scotland to the south of England, were used by organised crime groups involved in prostitution, cannabis farming and illegal immigration.

Fake tenant and criminal mastermind Feng Xu used a variety of identities and aliases supported by false documents such as payslips, utility bills, bank statements and references, in order to get through high street agents’ normal vetting checks. It is thought that he used at least 70 aliases.

He is said to have spent every waking hour on the phone to either letting agents or criminal gangs, organising a ‘business’ said to have made him at least £2m.

Despite, but in fact because of, the documentation and the referencing checks, agents actually had no idea who he was.

When National Crime Agency officers raided Xu’s flat in Birmingham and a secure storage unit he also used, they found 31 fake Chinese and Portuguese passports, along with numerous ID documents and £94,000 cash.

NCA investigators also found a computer database held by Xu listing 446 different addresses which he had been involved in renting and then letting out.

Once rental agreements were signed and keys collected, the properties would be handed over to criminal groups who then set them up as brothels, cannabis farms, or for people trafficking purposes and to house illegal immigrants.

Xu, 43, operated this network of properties for at least three and a half years until his arrest. Over the course of that time more than £4m in rent was paid out to agents .

During that time police forces across the country raided numerous properties rented by Xu. When each building was ‘busted’, the mystery tenant would disappear, leaving the police questioning agents over fake IDs and other documents.

Where Xu had tried ID and other documentation once on agents, he simply took the documents out of circulation and did not contact the same agent again.

When it started to become clear there was a connection between the incidents recorded by no fewer than 34 separate police forces,  the investigation was taken on by the NCA.

Using financial information and online clues NCA investigators were able to identify Xu, a Chinese national who entered the UK in 1996 as a student, but had been living illegally here since 2000, as controlling the rental properties.

He was arrested in May after being seen visiting agents up and down the country.

At a hearing at Birmingham Crown Court in October, Xu pleaded guilty to 22 offences, including fraud and money laundering. Three other charges were left on file.

At the same court last Friday, a judge sentenced him to seven years and four months in prison. He will face deportation after serving his sentence.

National Crime Agency branch commander Martin Grace said: “We believe that this case goes way beyond one man.

“In taking Xu out, we will have caused significant disruption to a number of different organised crime groups involved in prostitution, people smuggling and drug production.”