When two foodie brothers realised a pocket guide based on the opinions of restaurant-goers didn't exist for London, they launched Harden's Guides. Today, 8,000 people contribute reviews to the books

Richard Harden We launched Harden's London Restaurants guide in 1991. Peter had worked in New York and I had worked in Düsseldorf, and both cities had handy pocket restaurant guides of an opinionated sort that actually told you something useful. We could both see that there was a need for such a book in London and it seemed a classic gap-in-the- market opportunity.

Peter Harden I would have to credit Richard with the idea. We were both home for our father's 60th birthday and I was looking to come back and work in London. I was describing the fantastically boring job offer I would have to accept. We had idly turned around the idea of doing a guide. Richard thought we could do it.

RH I was a merchant banker and Peter was working as a junk bond analyst. We both ate out a lot and I used to regularly visit Peter in New York. In the late 1980s and early 1990s New York was way ahead of London as a dining out destination.

PH My nickname in college was "Hoover" Harden, which doesn't imply great discernment but does imply a passion for food. When I lived in New York I was in a lucky position as a somewhat overpaid young banker miles from home with little else to do other than go out and have fun. I was probably able to have culinary experiences beyond my years.

RH Zagat is almost exactly 10 years older than us. When we started it had achieved success, but had not yet become the phenomenon that it became in the mid-to-late 1990s.

PH I get slightly irritated when people say, "you just took the Zagat formula". Clearly we took a lot of inspiration from them, but we run our survey in a different way, we present our information differently, and our marking system is very different.

RH There are about 1,500 restaurants in the London guide and I would guess there might be 100 that we have never been to. They would tend to be peripheral restaurants, geographically speaking. But if it is peripheral then it is probably not that important.

PH It has been interesting to watch the East End of London develop. The idea of anyone opening a restaurant of any quality there wouldn't even have been funny when we first started. They had only just built Canary Wharf.

RH Peter has done more on the technological side and has done great work on developing the electronic capability of the business, which is fundamental. I have done more editorial and website work. When there are any big decisions we both make our contributions.

PH We always used to do everything in the business and that is a recipe for disaster. I think you need clearly defined roles that follow your strengths but also allow for the fact that one person needs to do one thing and the other needs to do another thing.

RH I admire Peter's tenacity. We have done deals with big companies like Vodafone and News International and we have never found that these companies with vast resources were able to throw up any technical issues that we haven't been able to address ourselves. Peter has enabled us to play with the big boys beyond the level I expected at the beginning.

PH Business is all about expressing opinions. Richard's conviction can be very impressive, although it is not always helpful.

RH Some people are actually obsessed by restaurants. We're interested; we like to talk about them, but it doesn't mean we want to talk about them all the time.

PH The business has been an overwhelming force in my life and you do worry about it just hoovering up your whole personality. When you meet people for the first time socially it is all they want to talk about, which is nice but it is also limiting in certain respects.

RH The UK is not actually that replete with interesting restaurants despite all the ballyhoo. We have done a UK guide for the last 10 years and it is a big operation, but the density of worthy restaurants that we find outside London is not much greater than what we have in London alone.

PH Blood is thicker than water. As a family enterprise you have that closeness and the feeling that you are there for one another. Quite often if you're in an organisation you have a sense of belonging but you may feel that it's rather spurious and wonder whether there is a real connective purpose.