Biba has launched an attack on the FSA for its failure to reveal information about four underwriters the broker organisation is investigating.
Biba head of technical services Peter Staddon is currently investigating the regulatory status of four underwriters based offshore but writing business in the UK.
He claimed that the FSA is aware of the underwriters involved and should clarify the situation regarding their regulatory status.
"I'm sorry, you are the regulator, that's what you should be doing," he said.
"They scream transparency. Let's be transparent about this."
Staddon declined to name which underwriters Biba was investigating, or disclose their locations or the amounts of premium involved.
An FSA spokeswoman said that anyone wanting to check the regulatory status of an insurer operating in the UK could search the register on the FSA website using the company's name.
She said such a search would indicate if the company was authorised to do business in the UK.