Valentino SS15 campaign

His other great advantage is a vast bank of data. With nearly 15 years and millions of transactions to pick over, he has become a font of retail information and it’s a joy to quiz him about the world’s shopping habits. Who are the serial returners? “The Germans,” he says. “They’re the worst.” And the least likely to shop during office hours? “The Japanese are the most ethical guys. They only ever shop after midnight. They don’t sleep.” (The Brits tend to shop late afternoon and evening and, though he won’t speak ill of his countrymen, it’s pretty clear from his facial expression that Italians like to do it at their desks.) The Spanish prefer red while the Italians love purple. Men are more loyal to brands and 65 per cent of transactions are undertaken by women, except in China, where the reverse is true.

It’s a game I could play all day. “It’s a sociological dream,” he agrees. It’s also valuable. For example: “We found out that when women buy shoes, in two-thirds of cases they only buy shoes, they don’t mix the cart with anything else. It’s a very focused category. Which means that, after analysing 8m orders with shoes, we launched a website for shoes only [shoescribe.com], because we knew what women want. The power of information is huge.”

If I were a luxury CEO, I would insist Marchetti be at every meeting. But, he says, luxury has been fairly reluctant to harness the power of his data. “Historically, it’s an industry that drops down from creativity to the customer – data have not been so essential. But I do my bit and I’m sure that they will come.”

Perhaps it’s just as well. If all we were being offered were things based on web sales, our wardrobes would probably be directed by housewives in Texas. Besides, while Marchetti knows what sells, he still doesn’t know why.