"Our only issue is with the three big brokers . . . Willis, Aon, Marsh, " said general manager Colin Morgan. "We've a lot of support among brokers at large in Ireland and the UK, with 600 of them on our books in England alone. We're not asking the big three to hand us the business. All we want is an opportunity to quote for it."

The blacklist is already beginning to crumble because some companies are bypassing the big brokers and placing their business directly with Quinn, Morgan claimed.

The maverick company, which claims to be the thirdbiggest player in Ireland, made its name in motor insurance by squeezing out the middleman and offering cut-price cover direct to car owners by phone. But it had to change tack when it expanded into commercial lines, such as liability and property cover, because businesses still need the advice of brokers in deciding their insurance needs.

The refusal of Willis, Aon and Marsh to play ball led to a public row earlier this year when Quinn accused them of operating a cosy cartel. The brokers responded that they could not place business with an underwriter that does not have a security rating from an agency such as Standard & Poors or A&M Best.

Senior industry executives have told the Sunday Tribune that Quinn will remained handicapped without a security rating.

"Our shareholders would never allow us to put policyholders at risk by placing business with people who do not have security clearance from S&P, " said one source. "They need certainty that the underwriter will still be around in 10 to 15 years' time. Quinn may talk about cartels but there's no doubt that big brokers have rules that prevent them giving him the business."

Quinn's growth plans involve certain niches within commercial lines and it hopes to grab a bigger share of the property insurance market in particular. In addition to growing its existing businesses in Ireland and the UK, Quinn will move into Belgium and the Netherlands from next year.

"The Quinn Group is involved in many businesses and this gives us a unique insight into the insurance needs of many different industries, " said Morgan. "We have first-hand experience of operating in many of the businesses that we insure."

This hands-on approach is also evident in the way the insurer invests premium income, which accounted for almost one-third of the pre-tax profits of 123m that Quinn reported for the first half of the year.

Company founder Sean Quinn takes an active interest in this side of the business and he accepted personal responsibility for the big losses incurred when the company bet heavily on technology stocks at the height of the dotcom boom.

Quinn no longer sits on the insurer's investment committee, although it is believed he has lost none of his enthusiasm for the stock market.

"There's no question that Sean still takes a deep interest, although he now has a bigger team of advisers around him, " said one source.

"The tech bubble was a hard lesson for him, as it was for others. He may have adjusted his style but not his enthusiasm. If he likes something, he's still prepared to follow the money."