The Financial Services Authority has issued a warning to West Midlands consumers who may have taken out an insurance with H&O Insure.
The FSA believes the company is offering invalid motor insurance policies.
The organisation said it had evidence that H&O Insure policies had been issued to people in and around Birmingham area.
However, the extent and location of all policy sales is still unknown.
H&O Insure claims to be based at 4 Equity House, 42 Central Square, Wembley.
However, the FSA said that the address is empty and awaiting demolition. There is also no trace of the company on the register maintained by Companies House.
The company is not authorised by the FSA to act as an insurer, which makes their policies invalid.
The FSA has warned that anyone who deals with an unauthorised firm will not have access to its financial services compensation and complaints schemes.
"Drivers who have bought motor cover through this company may be committing a criminal offence by driving without valid insurance," the organisation said.