A Wakefield estate agents was targeted by HMRC inspectors as part of a crackdown on money laundering.
Around 50 estate agents around the country were hit with unannounced inspections after they were suspected of trading without being registered, as required, under money laundering regulations.
The visits came as HMRC published the latest businesses hit with fines for failing to comply with the regulations.
This included one company receiving a £215,000 fine, although the company in Wakefield has not been named.
HMRC will now take action against the visited businesses who have failed to comply, which can include fines, publication and criminal proceedings.
John Glen, economic secretary to the treasury, said: “The vast majority of estate agents play by the rules and help us to crack down on dirty money, but I have zero tolerance for firms prepared to turn a blind eye to the law.
"Money laundering regulation exists to help protect honest business, so anyone who flaunts the law should know that swift action will be taken.”
Simon York, director of HMRC’s Fraud Investigation Service, said: “Estate agents need to understand that criminals prey on weaknesses, so it’s vital they take all steps to protect themselves. The money laundering regulations are key to that, but there’s still a minority of agents who ignore their legal obligations.
"These inspections are a wake-up call that if you continue to trade illegally we will come knocking.”
This is the first such week of action involving intelligence-led, co-ordinated activity aimed at estate agents trading without registering with HMRC as legally required.
The visits involved HMRC inspectors questioning the businesses to establish whether they were trading in breach of the regulations. Inspectors then assess whether any further action is required.
HMRC supervises more than 11,000 residential and commercial estate agents across the UK and helps these businesses protect themselves from criminals who use property sales to launder cash or finance terrorism.
Over the past three years, HMRC has carried out more than 5,000 interventions on supervised businesses, with 655 penalties worth £2.3m issued in 2017-18. In addition, HMRC recovered over £31 million under the proceeds of Proceeds of Crime Act.