Tucked away in a corner of the Clerkenwell branch of the Benugo food chain that he founded with his brother, Hugo, 10 years ago, Ben Warner is uncomfortable.
The trendily dressed Warner, a former chef who worked for Raymond Blanc but whose primary culinary education came working as a chef in the South of France, sits fidgeting with one eye on events beyond us as the interview begins.
"Every time I approach one of our stores, I feel slightly queasy," explains Warner, who was the first franchisee for the highly successful Pret A Manger group. "I rarely schedule meetings in one of our cafés because my mind wanders. I end up thinking: 'How long has that coffee cup been sat there?' or 'How long is the queue for service?' It makes it difficult for me to concentrate."
This might not make for the easiest of interviews, but such attention to detail has enabled Warner to build a a chain of sandwich shops and restaurants in London that has become the envy of its high-street rivals.
Indeed, the 23-store company has attracted the acquisitive attentions of much bigger competitors, including catering giants Compass and Sodexho. Benugo has also fended off "numerous advances from venture capitalists" keen to throw growth capital its way.
"We've been offered cash to sell up plenty of times, but we've resisted," says Warner, the brother of The Independent's business editor. "Taking the money from those guys would have been wrong. Hugo and I don't much like financiers. Sure we're in the business of making money too, but you shouldn't focus on profit to the detriment of everything else. Run a business well – and that means keeping attention to detail – and profits will follow."
And so far the profits have indeed followed. The latest accounts show a leap from £350,000 in 2006 to more than £1m last year, on sales of around £13m. Crucially, with the high street's fortunes hanging in the balance, Benugo isn't saddled with costly borrowings either.
"There were some dark times when we nearly went bankrupt – especially when we focused on Japan [where the company has some franchises] too much – but we never bounced a cheque and we survived. We more than survived and we haven't had to borrow money to develop the business either," says Warner.
Like its closest rivals, Pret a Manger and EAT, Benugo shelved plans for a public listing – "We looked into the idea but it wasn't for us," – but since then the company has merged with contract caterer BaxterStorey, allowing the Benugo boys to mull expansion. "One of the reasons we did the deal was so we could grow the business across the UK," says Warner.
But with talk of a looming recession, is it really a wise time to be pursuing such lofty ambitions? Doesn't the packed lunch come back rather quickly when money becomes tight? Apparently not.
"So far, we haven't felt any impact at all," says Warner. "Sales have continued to power on."
A dislike of financiers he may possess, but the City of London has proved to be a fertile hunting ground for Benugo during the past 10 years.
Benugo's client list includes the investment banks UBS, Deutsche Bank and Lehman Brothers, and it also has "pods" in the offices of accountants Deloitte & Touche and PricewaterhouseCoopers.
However, not all of the Square Mile's great and good make the grade with Benugo.
"We are asked to cater for a lot of City firms, but we are now in the enviable position of being able to say no on some occasions," says Warner. "One company we worked for was so arrogant that we stopped working with them. They subjected us to a hideous user group where there was an argument about the size of the carrot sticks that we sold. One wanted them longer, one shorter and the other liked them as they were. We were told to provide three different sizes. Ridiculous."
Ethics are central to the ethos of the brothers behind Benugo.
"Customers are looking for a provenance with their food these days," Warner says. "Is the packaging biodegradable? How many air miles have been clocked up for each product? Things like that weren't important to people a decade ago but they are now."
What has always been important to customers is price and Benugo has remained largely competitive, with Warner thanking his lucky stars that costs have been kept down by the influx of Eastern European workers into London.
Benugo may now be a fixture for City employees, but moves to spread the brand through deals with some of the capital's most famous landmarks are also bearing fruit. The company has just unveiled a store at the revamped Eurostar hub at St Pancras, and it already has a presence in the Victoria & Albert museum . Another swanky new restaurant was opened at the British Film Institute (BFI) on London's South Bank, and Warner is also bidding for the tender to run an operation out of the City's Museum of London.
"Sometimes the museum tie-ups can be highly profitable, but it depends on the exhibition of the moment," says Warner. "The recent Golden Age of Couture exhibition was fantastic: it was rammed for 12 weeks. In contrast, the Kylie exhibition [charting the rise to stardom of the singer] saw lots of fans come through the gates at the start and then it was relatively quiet. It's hard to know how many staff to get on board.
"The new restaurant at the BFI has received strong reviews, which is great," he adds. "The one dodgy one we got was from Fay Maschler (the fearsome restaurant critic of the London Evening Standard), who came in at 3pm on a Tuesday as things were winding down. You can't win them all, I guess."
Still, the venue has become something of a celebrity haunt, with Withnail & I star Richard E Grant recently seen biting into a chip butty. Other guests have included Noel Gallagher of Oasis, Office and Extras writer Stephen Merchant, as well as reservoir dog Quentin Tarantino and that luvviest of the luvvies, Richard (Lord) Attenborough.
Attracting stars to the showpiece BFI restaurant is one thing, but sustained success at Benugo will be based on continuing to attract the man on the street.
"We've learnt a lot of lessons over the past 10 years," says Warner. "I might not have time to row or do some of the other hobbies I used to, but I don't feel like I'm missing out at all."
Education: Wallingford School, Oxford
1982: Raymond Blanc, Maison Blanc – chef
1983: Prue Leith's School of Food and Wine
1983-1985: cooking on private yachts in South of France
1985-1990: broad range of entrepreneurial experiments in food-production business
1990-1995: founded Harry Masons – a chain of sandwich bars
1995-2000: original franchisee of Pret A Manager, overseeing three sites
1998 to present day: co-founder with brother Hugo Warner of Benugo – group of high-street café delis with original site in Clerkenwell
2005: Benugo wins contract to run the cafe at V&A museum
2007: Benugo opens at the relaunched British Film Institute on the South BankReuse content