Sean Quinn's latest business venture, which sees him go head to head with the giants of the life assurance sector, is not the first time he has played David to an industry Goliath. The self-made millionaire from Fermanagh has a long history of taking on established interests.

When he decided to set up a cement plant in competition with the CRH-owned Irish Cement in the 1980s most people thought he was mad. But the venture succeeded and nowadays, concrete and cement form the core of the Quinn operation with a new £70 million (€89 million) cement factory due to open in Cavan later this year.

His decision 10 years later to invest £60 million in a glass manufacturing factory in Fermanagh upset existing industry players, not just in the Republic but also in Britain.

It put him into competition with the dominant player in this state, the Ardagh-owned Irish Glass Bottle Company in Dublin, but he also encountered opposition from the Sheffield-based British Glass Confederation to try to find a way to stop the project. It failed and now Mr Quinn is planning a £180 million investment in a glass operation outside Manchester.

His latest onslaught is on the life assurance industry. After surprising the non-life business in 1996 with the launch of Quinn Direct, selling motor and household insurance directly over the telephone, he announced this week that the Quinn Group now plans to do the same with personal pensions, life assurance and investments.

It is the first time these products will have been sold over the phone in this State, a move described by one financial adviser as "very bold, very audacious".

But there are those who believe that Mr Quinn, who began his business life quarrying sand and gravel on the 23-acre family farm in Derrylin, south Fermanagh, may face a tougher task in his new venture.

"I think he faces an uphill struggle. The jury is still out on selling advice-led products over the telephone," says one insurance industry source. "With general insurance, there is an annual motivation to renew those products but the same cannot be said of the life assurance industry.

"Many of the products need a lot of advice to put them in place, particularly pensions, which makes them unsuitable for telephone and Internet selling."

Others query whether the Quinn brand has the credibility to attract customers making important long-term decisions about pensions and investments.

However, there are some who believe it suits Mr Quinn, whose operations continue to be headquartered in his Cavan stronghold, to be discounted by the Dublin insurance establishment before he even begins. "He likes being written off but conventional life offices under-estimate him at their risk," says one person who knows him.

There is little doubt Mr Quinn has come a long way since he set himself up as an agricultural contractor, rotovating soil for other farmers, in 1973. From there he moved into gravel, then concrete products and then cement with his decision to take on CRH.

In 1990, he decided to diversify, buying Parkes Hotel in Dublin, the Kilmore Hotel in Cavan and a few pubs. He now owns seven hotels, including one in Cambridge in England as well as Buswell's on Dublin's Kildare Street, 12 pubs and the Iveagh Fitness Club in Dublin.

Among his braver ventures was the building of the £14 million luxury Slieve Russell hotel in Ballyconnell, just south of the Border and close to the Cavan lakelands.

Again, Mr Quinn confounded conventional wisdom, which viewed the proposed hotel as a white elephant in the middle of nowhere. Known locally as Jesus, because the common reaction among strangers who suddenly see it pop up before them in the Cavan countryside is to take the name of the Lord in vain, the hotel has thrived and helped put the area on the map.

The Quinn Group's venture into the insurance market four years ago also appears to be paying off. Figures released by the group earlier this week, showing that Quinn Direct had 100,000 policy-holders and expected to report premium income of £60 million and pre-tax profits of £6 million for 1999 took many in the industry by surprise, belying rumours that the business had plateaued or was finding the going tough.

In person Mr Quinn, a former Fermanagh footballer, is described as modest and reserved, a man prepared to take risks but who always does his homework thoroughly.

He is well regarded locally where he is a major employer. In Cavan town, where some 200 people work in the direct insurance operations, the Quinn Group is taking account of its latest venture by building a new complex to accommodate 400 workers. Meanwhile, in west Cavan the glass and cement plants and the Slieve Russell employ many more.

"He is a man much admired for what he has done for west Cavan, Leitrim and south Fermanagh," says one local source. "Because of Sean Quinn, there is no unemployment in west Cavan, an area that traditionally would have had a high rate."

Despite living in Ballyconnell in Cavan, Mr Quinn is said to remain a proud Fermanagh man and his son and namesake, Sean, plays minor football with the northern county.

From modest beginnings, the Quinn Group has now grown to a position where it straddles concrete products, hotel and leisure interests, glass and insurance and the group appears prepared to consider most opportunities provided they meet its philosophy of offering a well-serviced, competitively-priced quality product.

The new insurance operation, Quinn Life, is closely modelled on Virgin Direct in the UK and while those who know him say that in personality terms, the two men are far apart, in many ways the Quinn empire increasingly resembles an Irish version of Richard Branson's in terms of its eclectic spread.

But success brings its own challenges and as the company has gotten bigger, so it has changed.

The group's recent High Court attempt to block a Co Meath cement plant planned by a competitor, Lagan Cement, raised eyebrows in some quarters.

The sight of the man who once took on the might of monopolies seeking to defend his own patch from competition prompted some to wonder if David had not become the new Goliath.