Despite his eventual success, Varsavsky’s decision at a young age to break with family tradition and try his hand at entrepreneurship did not go down well with his elders. “My family thought businessmen were thieves, but I think what we have at FON now is the perfect blend of socialism and capitalism,” he says. “There is an element of sharing, but ‘aliens’ – our term for surfers who are not signed up to FON – pay their way, and commercial establishments called ‘bills’ take a cut of 50% of revenue from fees paid.”

It sounds idealistic, but it seems to have worked well so far. Since its inception in November 2005 FON has become the world’s largest Wi-Fi network, and it is soon to become larger than all other Wi-Fi networks combined. The company launched by offering “social router” devices from Linksys and Buffalo – units with a street value of $60 – for a heavily subsidised price of $5. This might explain why there are now close to 300,000 registered “Foneros” worldwide and why Varsavsky, who counts Skype founder Niklas Zennstrom and millionaire Danish tech investor Morten Lund among his friends, felt the need to secure $22m in investments from Google, eBay, Index Ventures and Silicon Valley venture capital hotshots Sequoia Capital.

It’s an ambitious project, and Varsavsky estimates that the firm will need until 2009 to break even. Detractors who cast doubts on the company’s almost microeconomic business model – relying on millions of tiny transactions from the $3-a-day brigade, a bit like eBay – have missed the point. Varsavsky, although passionate about the revolutionary social implications of his offering, appears to be aiming to construct a business-to-business goldmine that will involve many of the world’s biggest telecom players approaching him for tie-ups, royalty deals and IP sharing. It’s very much the Google model – build an impregnable brand around a free product taken up rapidly by vast numbers of people, then leverage the brand for commercial benefit.

FON also appears to have an advantage over its rivals, the mobile phone operators. The European Commission’s recent move to cap international roaming charges does not extend to data, meaning that business travellers still face a massive bill when they use their laptop data card to connect to the internet when abroad, however briefly. “When I was in Japan recently I ran up charges of more than €2,300,” sighs Varsavsky. “Now, I like the internet, but not that much!”