Born in Moscow, and raised partly in London, Lebedev is an elegant 32-year-old with a Regent’s Park flat, a perfectly trimmed beard and a post-Soviet fortune. His father (about whom more in a moment) was a K.G.B. officer in the 1980s, and Lebedev went to elementary school in Britain. He returned to London for high school, and emerged into the public eye a few years later — now as the son of a very wealthy man. Back in those days, he and the actress Joely Richardson had themselves photographed wearing matching his-and-hers tuxedos. At that time, he was “romantically linked,” as the tabloids in London had it, with Geri Halliwell, the former Spice Girl, as well as the model Sophie Dahl. For a while, he was best known for hosting charity balls attended by Anjelica Huston, Vanessa Redgrave, Ralph Fiennes and J. K. Rowling, among others. Entertainment was provided by the Black Eyed Peas, Mary J. Blige, the Russian Olympic ice-skating team and the Kirov ballet.

A decade ago, in other words, he would have seemed, to the British, a lot like the other London Russians. For there is now such a thing as a “London Russian”: since the 1990s, London has become the city of choice for the new Russian business class. They find it more hospitable than Paris, more cosmopolitan than New York — and more law-abiding than Moscow. They’ve discovered that British banks are happy to manage their money, British courts are happy to hear their cases, and British tax law means that no one asks questions about their investments abroad.

As a result, some 300,000 Russians are now thought to live in the city, a staggering proportion of whom have seven-figure incomes. A few, of course — Oleg Deripaska, Roman Abramovich — are billionaires. Huge parts of the city’s financial markets are now dominated by Russians. Whole chunks of the real estate market, including Belgravia, Chelsea and choice bits of the countryside, are dominated by Russians now too. “Moscow-on-the-Thames,” also known as “Londongrad,” has its own Russian restaurants, its own nightclubs, its own summer and winter balls. Bodyguards in dark glasses lurk behind ancient hedgerows, guarding Russian oligarchs’ stately homes. It’s a world that exists in parallel with British high society, but rarely intersects.

If he’d stuck to party-giving and party-going, Lebedev might have blended right in with his compatriots, their large houses and their supermodel girlfriends. He might easily have become one of those playboys featured in magazines, or the subject of gossip about his cars and his yachts. But a couple of years back, Lebedev took a different turn. Instead of treating London as a convenient parking lot for his money, he decided to become part of it. Instead of keeping a healthy distance from British high society, he decided to join it.

Now the supermodels are gone, at least the obvious ones. Lebedev has sold his old office in Mayfair, a neighborhood best known for hedge-fund managers and ladies who lunch. Instead, Lebedev works out of his business offices and arranges other meetings informally at his flat. In conversation, there is no discussion of his money or what it can buy. Instead, he speaks in dead earnestness about investigative journalism, the future of the media, freedom of speech. At the moment, he is keen to talk about how he has helped turn around a failing newspaper, the Evening Standard, which he and his father purchased in 2009, rescuing its journalists, and thus striking a blow for freedom of the press. His proudest achievement to date? It is, he says, that “we’ve proven that the print media can still make money!”