Boris Johnson is Britain's version of Italy's Silvio Berlusconi, Ian Hislop has said in a documentary about the politician.
The former newspaper publisher said London's mayor was like the former Italian prime minister "but somehow funnier".
In the Michael Cockerell's BBC film, Boris Johnson: The Irresistible Rise, Conrad Black goes on to describe the mayor as a "sly fox disguised as a teddy bear".
Cockerell looks at Johnson's early life in Eton and his later career as a journalist, MP and latterly Conservative mayor of London.
The documentary reveals how the politician wanted to be "World King" and was highly competitive.
His sister Rachel Johnson says of the relationship between Johnson and the prime minister: "When they're together it's rather sweet because David Cameron - even though he's taller - looks at Boris as if he's still head boy.
"These relationships are set very early. It's like birth order. People shouldn't forget that. He was head boy and Cameron was two years younger. It gives Boris a sense of continuing superiority. Why wouldn't it?"
Also commenting on his nemesis was Labour's former mayor of London, Ken Livingstone, who says Johnson can "get away with a lot" because he "makes people feel good about themselves".
Cockerell, writing for the Radio Times, explains his impression of Johnson after making his film: "I asked Johnson if he had learnt a lesson for the future about the advantages of not learning your lines.
"'As a general tactic in life,' he replied, 'it is often useful to give the slight impression that you are deliberately pretending not to know what's going on - because the reality may be that you don't know what's going on but people won't be able to tell the difference'."
In a meeting with Cockerell, Johnson also spoke of his desire to become prime minister.
Pushing the 48-year-old for an answer, Johnson eventually said: "I would like to be the lead singer of an international rock group. That was my aim, or a good guitarist. I would love to have been a world-famous painter or a composer. There are many things that I would like to have been able to do.
"It's a very tough job being prime minister. Obviously, if the ball came loose from the back of a scrum - which it won't - it would be a great, great thing to have a crack at. But it's not going to happen."