(Corrects date of documentary in fifth paragraph.)

Political news in the U.K. has been dominated recently by stories about two very different men: Boris Johnson, the larger-than-life mayor of London and possible future prime minister, and David Miliband, the former British foreign minister, who wanted to be prime minister but has quit politics to work in New York.

Both stories struck a chord because they are human and relatable. Miliband is leaving for a job in New York because his younger brother Ed  -- or Miliband “Mi” for minor, as he would be called in a British private school -- defeated him by a whisker in the Labour Party leadership contest in 2010. Now, having been crushed in this sibling rivalry, he appears to feel he might as well leave because there is nothing left for him in his younger brother's shadow in the U.K.

Miliband will lead the International Rescue Committee, a humanitarian organization unknown in Britain. There are two points here: First, it isn't surprising that Miliband has leapt at the chance of a good new job, because he so royally messed up when he turned down the chance to be the European Union’s foreign policy chief in order to run for the Labour Party leadership. He lost both.

Second, going to New York may also be part of a bigger plan to get a big job at the United Nations. So, while Miliband senior may be destined for interesting things, he looks set to fade from British consciousness.

Not so, Boris Johnson. On March 25, the BBC broadcast a documentary about his life, in which Johnson refers to U.K. Prime Minister David Cameron as "Cameron Mi," recalling their time together at Eton. Cameron is the younger man by two years, and Johnson's sister Rachel says in the show that Cameron continues to view Boris “as though he is still head boy.”

The documentary charts the life of Johnson, ending with an oblique admission in his posh old-fashioned idiom, that he would like to be prime minister. “Obviously if the ball came loose from the back of the scrum, which it won’t -- of course it would be a great thing to have a crack at, but it is not going to happen,” Johnson says.

The fact that a politician admits he wants the top job isn’t normally hot news, but in this case it was. That's because fears are growing within Cameron's Conservative Party that he will lead them to defeat at the next elections, which must be held by 2015. Put Johnson in charge of the party, according to an opinion poll by the research agency YouGov last week, and the Conservatives would eliminate the six percentage point lead that Labour enjoys when the Tories are led by Cameron.  

A third of all British prime ministers went to Eton, so Johnson's background is far from unusual. What distinguishes him, including from Cameron, is that he has charisma. He is funny and has an uncanny ability to connect with people who aren't natural Conservatives. He makes a virtue of his mixed English, Turkish, German, Russian and Jewish roots and, as the documentary notes, he doesn't fit into the usual left-right categories of U.K. politics -- Johnson defends bankers and is pro-immigration; he is a euro-skeptic and favors gay rights. Both combinations are rare among Conservatives.

Johnson has had luck on his side. Cameron has to share power with the Liberal Democrat Party, and is prime minister at a time of recession and economic hardship. As mayor of London, Johnson has relatively few powers (and therefore responsibilities), as well as a fantastic stage on which to project himself. He presided last year over a hugely successful Olympic games that he had no role in securing for London, and oversaw the introduction of wildly successful public bicycles for the capital, now known as Boris Bikes.

Not everything has been easy for Johnson, including the riots that exploded in the streets of London while he was away on vacation in 2011. Still, Johnson was re-elected in 2012 to a second term, so it isn't surprising that many Conservatives see him as a natural winner.

Much of the U.K. press pronounced Johnson terminally damaged after a TV interview that trailed the BBC documentary, on March 24. The interviewer brought up that Johnson was fired during his career as a journalist from the Times of London for making up a quote, that he was also fired from a political post after lying to a former Conservative leader about an extramarital affair, and that he once told a friend and convicted fraudster in a taped phone call that he'd give him the address of a journalist, whom the friend said he wanted to have beaten up. (Johnson didn't provide the address, and the man wasn't beaten up.)

As Johnson fumbled his responses the interviewer said: “You are a nasty piece of work aren’t you?”

Although any one of these accusations might destroy many a politician, they don’t appear to damage Johnson. The YouGov poll, for example, was conducted after the tough interview, and Johnson's score increased from the last time the regular poll was conducted. One person interviewed in the BBC documentary jokingly refers to Johnson as “our Berlusconi,” a reference to former Italian Prime Minister Silvio Berlusconi. The comparison is absurd in one sense, especially as Johnson doesn't own a media empire, but it's uncannily correct in another -- namely that one secret of Berlusconi’s success is that many Italians admired him because they wanted to be him.

So, in calling their documentary “The Irresistible Rise of Boris Johnson,” the BBC was correct. It's hard to imagine anyone wanting to be Cameron or Miliband Mi. Compared with Johnson, these are two-dimensional politicians.

Johnson likes to say that his chances of becoming prime minister are only slightly better than being “decapitated by a Frisbee” or “reincarnated as an olive.” Don’t believe him for a second. 

(Tim Judah, the Europe correspondent for the World View blog, is a correspondent for the Economist and author of several books on the Balkans. Follow him on Twitter. The opinions expressed are his own.)

To contact the author of this article: Tim Judah at timjudah@btinternet.com.

To contact the editor responsible for this article: Marc Champion at mchampion7@bloomberg.net.