Only in desk-bound corporate Ireland, where the humble sandwich has been literally fuelling the State's growth for the last 20 years, does the phrase "the best thing since sliced bread" actually mean something.

And reaping the reward of our national hankering for triple-decker meals is O'Briens Sandwich Bars, which this week appointed Fiacra Nagle as its new chief executive.

O'Briens was founded in 1988 by entrepreneur and now would-be politician Brody Sweeny, who has overseen its rise from a single sandwich shop to an international franchise operation with almost 300 outlets in 13 different countries.

Nagle's background is in banking and finance, rather than catering or retail, but he feels that this will help him drive profitability for the company and the store franchisees.

"I bring a different level of skills. I'm more focused on the metrics of the business, on measuring things within the business at a retail level. I bring a little more rigour on the day-to-day operation of the business," he says.

The changeover has been on the cards since 2004, and will give Sweeney enough time to prepare for his upcoming general election campaign as well as letting the dust settle since O'Briens's major rebranding process early last year.

"I don't see any major changes in strategy. Last year, we invested about €1.5 million across the UK and Ireland in our rebranding concept and that is now in place.

"So my major challenge is constantly looking at the brand offering and the retail offering and driving our retail sales through our stores.

"The other focus that I have, and I have said this internally as well as to franchisees, is to drive profitability. It's a very competitive and challenging market in Ireland and I need to make sure they have the armoury at the retail level so that they can compete effectively."

O'Briens faces a crowded marketplace, both here and abroad, as the market changes to suit modern lifestyle trends.

"When we started off, there weren't a huge amount of competitors and we were doing sandwiches, coffee and soup as the main cornerstones of the business," says Nagle.

"Now there are expanded food concessions in convenience stores like Spar and Centra and you have your Insomnias and your Café Sols, and there is a similar list of new entrants in the UK.

"The reason behind our investment in the brand over the past 18 months is to reposition the brand to where we thought I should be.

"We are the market leader; we have over 100 stores in Ireland. We are a major Irish brand, we've brought in a new management team and I want our brand to be seen as the leader in the sector."

Nagle came to sandwiches through the unorthodox route of international finance. He had been in banking since college, both here and in London and had greatly enjoyed his time there.

However, he felt the need to get involved in the hands-on running of a business and he had been pondering a career change for a while before he and Sweeny first crossed paths.

"I joined Brody in early 2000, the start of a new millennium and the start of new venture for me," says Nagle. "I had been working in international banking for 15 years, the last eight with CBC in the IFSC.

"When I met Brody, he was looking for someone to work in the business with a different approach. A lot of the people in O'Briens were from catering backgrounds or had been with the company from the early days and I came in with a new approach."

Nagle's rise through the company was rapid. "I started off working in international development. At that stage, we had just started business in Singapore and Australia," he says. "Then I was involved in the franchising side in Ireland and the UK, and after that I got involved in the property side, and about two years ago, I took on responsibility for running the Irish business.

"When I look back now, it seems like a natural progression that brought me here. I did a BA in economics in UCD and MBS in banking and finance, so as you can see, I am perfectly qualified for the sandwich business!

"I have no regrets in leaving banking, I am passionate about this business and I wouldn't have taken on the role if I wasn't."

In the year ahead, O'Briens expects to open around 20 stores in both the UK and in Ireland, around the same as last year.

Internationally, Nagle feels the focus will be on western Europe; Scandinavia, France, Germany and Italy.

Nagle also wants to expand retail offers, rather than introduce new food lines.

"Our stores are generally running to full capacity during lunchtime, so we need to look outside that, to breakfast service and mid-morning and mid-afternoon. Outside catering, both corporate and private, is very important as well, as you are not relying on the retail alone."

Nagle admits that he won't be trying to emulate Sweeney, or replace him as the face of the business. "I don't see myself ever having the same high profile as Brody. I'm a different style of operator. He will always be associated with the brand and I hope I will be associated with it as well, but in a different way," he says.