We are one of the biggest textile manufacturers in the world and certainly the biggest purchasers of cashmere. When I was young, I spent summers working with the sales team in Paris and London - that's where I learned to speak French and English. Other factory owners sent their kids to Australia and New Zealand to learn how to sort wool, but I think my father had a lot more insight. We often travelled to Mongolia and Tasmania to buy cashmere, making sales calls in Hong Kong. He was open-minded and everyone, even the best couture houses in Paris such as Christian Dior and Givenchy, bought fabric from him. By 1975, our factory employed 300 people. It was big for our area, but small for the world.

When my brother and I took over in the 70s the world was changing. We knew we not only had to become specialists, we also had to branch out into ready-to-wear. The progression was natural. We started by making cashmere scarfs in different colours to give to our clients. They'd say, 'Hey, Sergio, how about making a blanket for me.' So we did. Then they'd say, 'Hey, Sergio, how about making a sweater for me?' We did that too. The ready-to-wear collection evolved from that. Our family is fascinated by horses, so we made a jacket for riding. We love to sail, so we made a jacket for sailing too. That's why we don't have a designer. My wife and I talk to the design team about what we need as real people, because at the end of the day we are not trying to sell a fantasy or a hot seasonal look; we are the kind of people who wear our clothes.

We've grown by word of mouth. There are a lot of celebrities in Hollywood who wear our jumpers, but I don't need to use them in advertising campaigns. I am also not going to tell everyone that the king of Spain asked me to outfit his entire crew on his yacht. I think it's better not to be too outspoken, but be part of a small circle.

I have a cook and, when I'm not in Milan or travelling, I try to go back home every day for lunch. Usually, it's something simple. If I eat pasta or heavy foods I fall asleep in the afternoon. Although it's a light meal, I like it to be presented properly, with proper settings. We may just have a salad but there will be six types of olive oil on the table. For me, the raw materials are most important.

I try to eat with my children. I have a daughter who's 15 - she's the most like me - and there are the twins, one boy and one girl, who are 11. I am taking all of them to summer school in the United States. The twins will go to Camp Robin Hood [in New Hampshire] and my oldest will attend Phillips Academy in Boston. I want them to speak native-standard English. My English is alright but when my children grow up, they will speak fluent Italian and English, which is a good mix. Every summer I also go sailing with my family in Portofino, and I will go with them again this year.

In the afternoon I may head back to the office, which is behind our store in Milan's Via Montenapoleone. My brother and I take turns heading the company. We do three-year terms each time. I also have another sister but she's not involved in the business. I am on the phone constantly. We have stores opening around the world, and we own each one so we have to manage everything ourselves, from design to presentation to location. We just opened a store at the IFC Mall in Central and one in Las Vegas. I am in touch with my suppliers all the time to ensure we get the best material available. If there is a good source we buy all of it.

The finest wool comes from the vicuna, which lives high in the Andes. The fleece is silky smooth. The species, a cousin of the llama, was almost extinct because so many were killed for their fur fibres. We worked with the Peruvian government to protect the species. We pay a fair price for them. They are extremely expensive - much more expensive than the best cashmere in the world - but that's why the vicuna has survived. There are now about 200,000 and we reserve the fabric for our bespoke suits. We have a lot of Japanese and American customers who know about this.

I don't go out much in the evenings because my wife and I enjoy living up in the mountains. I read after dinner, usually business magazines because that is my main interest. My kids don't require too much attention now. They tell me to go away when they are playing on the computers. I don't tell them what I want them to do when they grow up. For me, it was natural to take over the family business; there's nothing else I thought of doing. That's a very Italian way to look at things. I have two more years then my brother Pier takes over again as CEO, so there's still a lot I need to do.'