London-based broker CSI Ltd has been forbidden from accepting premiums by the GISC.
The action was taken as a result of an intervention order made at a meeting of the GISC enforcement committee last week.
The order forbids CSI from accepting premiums "of any kind" and also forbids the broker from "disposing of or otherwise dealing with its insurance transaction assets without the prior consent of GISC".
CSI operates from offices at 125 Putney Bridge Road, Putney, London. It brokes a range of personal lines business including motor, home and contents, jewellery and fine art cover.
CSI initially traded for ten years as a franchise of Coversure Insurance Ltd before completing the transition to CSI Ltd in July 2000.
Meanwhile, under new rules, firms applying for GISC regulation will have until 1 July 2004 to submit their applications for membership.
The decision was taken to prevent firms exploiting the FSA's agreement to offer "due credit" to GISC members in good standing.