In unwitting homage to the convoluted path trod by the legendary Latin revolutionary Che Guevara, screenwriter Peter Buchman took the circuitous route to working with Steven Soderbergh on the director's films Che: Part One and Part Two that IFC is releasing in North America this week.

Through a series of stops and starts, Buchman, who had quit his work as a playwright in Seattle and moved to Los Angeles to pursue his screenwriting career, found himself boarding a plane to New York about four years ago to meet Soderbergh.

Buchman had heard the Oscar-winning film-maker was having trouble with a script he had inherited from Christopher McQuarrie for a Che Guevara project to star Benicio Del Toro. This was his chance - Buchman had discussed working with McQuarrie on an Alexander the Great project that fell through and had already undertaken some research on the iconic Guevara.

The meeting with Soderbergh was positive and before long the pair were making a movie together. "We tried to create an objective portrait of Che in a way that felt like we saw the real man," Buchman says.

The initial plan was to make one film starting in 1956 with Guevara's role alongside Fidel Castro in toppling the Cuban regime of Fulgencio Batista, and culminating with his death 11 years later during an attempt to stage a coup in Bolivia.

Buchman and Soderbergh travelled to Cuba and Bolivia and spoke to participants in the historic events, then in January 2005 went to New York to shoot the sequences where Guevara addresses the United Nations as head of the Cuban delegation in 1964. "But Steven thought it wasn't doing justice to the story to compress it into one film," Buchman recalls, "so I went off and rewrote it as two separate movies."

The Cuban sequences were shot in Puerto Rico and parts of Mexico in autumn 2007, while the Bolivian expedition that forms the core of Part Two was filmed in rural Spain and La Paz, the capital of Bolivia. "We kept a very high bar for historical accuracy," Buchman says. "It was the story of his rise and fall, basically. It's remarkably timely to tell this story. Even with globalisation there's still a lot of inequality in the world so I think a lot of the issues Che was fighting for are very relevant today."

Buchman enjoyed working with Soderbergh. "He's very collaborative; I can argue with him about anything and the best idea will win," he says. They are now collaborating on Making Jack Falcone, about undercover FBI agent Jack Garcia.

He is also working on The Piano Tuner, which Werner Herzog is directing, and has just written The Wonga Coup for Miramax, about former mercenary Simon Mann, who was arrested for trying to overthrow the leader of Equatorial Guinea, an episode that involved former UK prime minister Margaret Thatcher's son, Mark.