The FSA is putting together a team to conduct pre-authorisation visits of brokers. According to an insider, the regulator is pulling new supervisors into a specialist team to visit larger brokers before they receive 'minded to authorise' letters. "This will be the litmus test before regulation begins," the source said.

Marsh, Willis, Aon and Alexander Forbes are among the companies to confirm they have received a pre-authorisation visit.

The source said the FSA had asked one firm to "prove its solvency and provide financial projections going forward".

An FSA spokesman said the visits were conducted when the FSA had a question "beyond the application form". "It is a check to see if they meet the threshold conditions," the spokesman said.