Panama is that long, skinny bit on the map that links the continents of North and South America. Because it's in the tropics and has the Atlantic on one side and the Pacific on the other it's hot, humid and wet for eight months of the year and hot, humid and dry for the other four months. That's the kind of weather that's a paradise for malaria mosquitoes, the very insects that killed a staggering number of the men who worked on the construction of the Panama Canal. Panama is probably best known internationally for three things - the famous national hat, the infamous '80s regime of General Manuel Noriega - but mostly it's known for the canal that connects the two major oceans.

The canal was built and operated by the Americans, who virtually created the state of Panama and kept, as part of the first treaty with their client state, the Canal Zone - a five-mile-wide strip on either side of the canal that was sovereign American territory. The canal was opened officially in 1920 and it has been the subject of many treaties between America and Panama over the years. The control of such a vital element of American national interest was something the Americans wouldn't cede lightly. It was officially handed back to the Panamanians in 2000, but the Americans still retain the right to intervene militarily. And it is in Panama that John le Carré set his 1996 spy thriller "The Tailor of Panama". Later he turned the book into a film script which ended up at Columbia studios.

You can almost imagine the scene in the studio boardroom. "This script is set in the tropics. Get me John Boorman." Actually there's a scene in Robert Altman's "The Player" with virtually the same line. Looking through Boorman's extensive canon of work, you can't help but notice how many of them are set in hot places. "Hell in the Pacific", "The Emerald Forest", "Beyond Rangoon" and now "The Tailor of Panama".

I still remember meeting John le Carré when I was sixteen and running the school's film club. We'd shown "The Spy who came in from the Cold" and le Carré gave us a talk after the screening. He looked the classic English bucolic gentleman; tweeds, a Vyella shirt and stout brogues. To us young trendies of the sixties he looked very old school. He confirmed our prejudices at once, as the first thing he told us was that he'd picked le Carré as a pen name, because in French it meant "square".

"The Tailor of Panama" is in some ways a departure from his other spy thrillers of the cold war era, since it has an element of black comedy. For Boorman too, it was an unusual departure not to originate the script - in the past he's mostly been his own scriptwriter. This time he collaborated on the script with le Carré, whose works have up to now translated somewhat better to television than they have to film. I asked John Boorman why this might be so. "Adapting his work for film is difficult because of the structure of his books - because they're complex and there's a wide range of characters and sub-plots." "The Spy who came in from the Cold", "The Russia House" and "The Little Drummer Girl" have all been filmed, but le Carré's greatest successes have been the adaptations of his books for television. "Tinker, Tailor, Soldier, Spy" and "Smiley's People" worked well because there was time for the characters to develop. One hundred minutes of film gives a lot less latitude to the film-maker. "To make it work for film the adaptation has to be fairly redical; the whole ending - in fact the whole last third is completely different." A lot of writers can get very protective of their works and hate seeing it changed, but "unlike many authors, he was not only willing to see changes made, he welcomed them."

Even after the film had been shot and a rough-cut had been done, there were still changes to be made. The title role - the tailor Harry Pendel - is played by Geoffrey Rush, who won his Oscar for his role in "Shine". Rush brought his usual skills of preparation and diligence to the role of Harry. Before leaving home in Australia he took tuition from a tailor in Sydney to learn some of the skills. Packing his bags and flying off to join Boorman and assembled company in Panama City, he spent time with another tailor who taught him the mechanics of chalk and cut. "It's amazing the knowledge you acquire for a film", explains Rush. "I faked my way through Rachmaninov in "Shine" and then I tailored a waistcoat for "The Tailor of Panama"."

Pierce Brosnan plays the British spy Andy Osnard. It was after seeing him in "The World is not Enough" that Boorman decided to cast him. "There was something in his performance I hadn't seen before, and that convinced me Pierce could be Osnard," he explained. But one of the first problems Boorman encountered with preview audiences was the character Osnard. People arriving at the previews only knew that Pierce Brosnan played a spy - consequently expectations of Bond ran high. But "Osnard is the anti-Bond, a man without a moral scruple or a single unselfish thought", says Boorman. Many of the female viewers found that hard to take. Watching their suave hero suddenly start to brutalise women had some preview audiences literally gasping in shock. Others waited for half the movie to watch Osnard redeem himself and come good, which unfortunately doesn't happen. Osnard is irredeemably bad. After analysing the preview audience responses it became clear that it was necessary to shoot a couple of extra scenes for the beginning of the movie to establish at once that Osnard is no James Bond. The other major change was re-shooting the end. Hollywood really doesn't like unhappy endings.

This isn't the first time that Boorman has come across the "Bond Factor". When Sean Connery gave up the Bond role he went for a long time without work. Nobody wanted an ex-Bond. It was Boorman who gave him the lead in "Zardoz", and they've been friends ever since. There's no doubt that moving away from Bond is a difficult transition to make. For Brosnan there was fun to be had because, unlike Bond movies, a universal certificate wasn't a pre-requisite. Whereas in Bond movies sex and violence has to be sanitised to the point of unreality, Brosnan was able to get his teeth into something considerably more meaty in the "Tailor". "Pierce relished the opportunity to throw off the mould," says Boorman, "and he relished doing real sex scenes." For Brosnan there was a major incentive to play the role: "The lure for me was John Boorman, John Boorman, John Boorman," he says. Although the role is that of a British spy, Osnard is a million miles away from Bond. "Osnard is loose and baggy, compared to Bond," explains Brosnan. "He's on the point of retiring from the field, he's disillusioned, he wants to make one last hit and then he's out of the game. He's a womaniser, he's cynical, and he's manipulative."

It was Pierce who reminded Boorman of a day that almost ended Pierce's acting career. Boorman had auditioned him for a part in "Excalibur" and had decided not to cast him. Driving home in cold London rain after this rejection, his elderly car broke down in heavy traffic and he walked home wet, and in a state of dejection. The portents were there, he thought, he'd have to give up the idea of a career in films. Thankfully for film-goers, his career did take off and flourish. "I missed it," says Boorman, "I didn't have the insight to see beyond his audition to what talents he undoubtedly had."

Boorman has never been shy of political themes in his movies. "Beyond Rangoon" portrayed the violent excesses of the Burmese Junta with harrowing accuracy. This time the politics revolve around the canal. Without giving away the story, it's a scathing attack on the American right, which given the recent election, might make the movie something of a political hot potato. It wasn't that long ago that the Americans handed control of the canal back to the Panamanians and it's in this historical period that the film takes place. Recently George Dubya Bush has said that if he feels there's any threat to American interests over the canal, he'll take it back. Remembering that father George wasn't slow to go into Panama to arrest Manuel Noriega, the threat might just have some teeth. Against this backdrop the film is peopled with diplomats and spies both English and American, all of whom are venal and materialistic, while some are simply bad.

Perhaps the only two characters who are normal decent people are the two main female characters; Harry's wife Louisa, played by Jamie Lee Curtis, and Marta, Harry's business partner and conscience, played by Leonor Varela. Jamie Lee Curtis has been a friend of the director and his family since she and Boorman were on the Jury at the Cannes Film Festival in the early '90s. He explained why he cast her: "Jamie Lee Curtis is self-possessed, but underneath she is very fragile. That was how I saw Louisa." I got to know her a little while she was in Ardmore filming and found her as entertaining and funny as some of her screen characters - the ones in a "A Fish called Wanda" and "Trading Places" come to mind.

I spent a day filming at Ardmore for a scene in which I had only to sit and smoke a cigar - not bad work if you can get it - and got the chance to watch not only Geoffrey Rush and Brendan Gleeson working, but also Leonor Varela. Later we talked in her dressing room. The role of Marta offered a challenge to twenty-six-year old Leonor. "When the script for "The Tailor of Panama" arrived, I knew I would do anything to be in this movie," she said. "I auditioned for John, and he cut straight through my artifice; he gave me such a lot of help in a few minutes. I felt really good and I knew I had the part". Marta has been physically scarred by Noriega's goons, the secret force of the corrupt regime that once operated in Panama. She's a good woman: she runs Harry's business, she loves Harry and is fiercely protective of him. "She sees through to the heart of things. She sees Harry's strengths and his weaknesses. She sees through Osnard," Leonor explained. "She is very calm and doesn't choose to be involved in any dissent: probably because of the time when she did."

Irish audiences will instantly recognise Brendan Gleeson, who plays the streetwise Mickie Abraxas. Because he isn't physically a typical Panamanian, Brendan dyed his hair black and wears dark contact lenses to help himself slip into his Latino character. He even adopts a realistic Panamanian accent. Actor/director David Hayman plays Osnard's boss, Luxmore, who finds he needs to personally oversee the final act of Osnard's cunning plot. John Fortune plays the British ambassador Maltby, a naïve participant in Osnard's ambitious scheme. And Britain's leading playwright Harold Pinter makes one of his rare acting appearances as Harry's Uncle Benny - his dead mentor - who, in times of crisis, appears to Harry. And while I'm listing the actors, I can't finish without remarking on the extraordinary performance of Paolo Tullio in a five-second segment, playing a Panamanian business man who annoys Pierce Brosnan on an aeroplane. Definitely one of the highlights of the film, I thought.

Boorman is a consummate filmmaker who inspires trust in all who work with him. "I like the variety of the process," he says, "writing is solitary, directing is public and producing is about holding it all together. I'm often asked if there isn't a conflict, doing all these jobs. As the director I often curse the writer, while the director often falls out with the producer. As I'm all three, I'm usually at war with myself."

The film got its first public screening at the Berlin Film Festival on the 11th of February, where it recieved a great deal of critical acclaim. It was there as an Irish entry in the competition. It had an all-Irish crew, with the exception of Philippe Rousselot the cameraman, and after six weeks filming on location in Panama, there was a further five weeks shooting in Ireland, all on set in Ardmore Studios. Boorman has had a long connection with both Ardmore and Ireland. He's lived here for over thirty years and was for a time chairman of Ardmore Studios when it was a state enterprise. Most of his considerable output has had an Irish connection, and specifically with Ardmore Studios. Beginning in 1969 he did the post-production of "Leo the Last", "Deliverance", "The Emerald Forest", "Where the Heart Is" and "Beyond Rangoon" there; four weeks of model shooting for the "Heretic"; produced "Angel" there; edited "Hope and Glory" there and shot "Zardoz", "Excalibur" and "The General" entirely in Ireland. Over thirty-two years few can claim to have brought so much to the Irish film industry - a point that is often overlooked.

For directors, film festivals are something of a chore. I saw Boorman's schedule of interviews for the Berlin festival: one every eight minutes during an eight-hour day. They were broken down into TV, radio and print, and represented every country in Europe and even places from the far East and beyond. Oddly, the only country not represented in any of the media covering the festival was Ireland. I asked Boorman if he minded doing such intensive days of interviews. "I don't enjoy it, no. A few years ago I was in New York promoting a film and I ran into Federico Fellini and Marcello Mastroianni in a shop. Fellini asked me what I was doing in New York and I said "doing interviews". "So am I," said Fellini, and added, "You know, John, as directors we should make a different deal. We wouldn't get paid for making the movies - after all we enjoy doing that - instead we should get paid for doing the interviews."

For the moment some of the executives at Columbia seem a little unsure as to how to market the film. The most obvious line for publicity - "See Pierce Brosnan in his new spy thriller!" - isn't going to work; the previews made that clear. Perhaps too, there's a little fear of the fundamentalist right who fare badly in the film and are now back in the White House. A few swipes at Bush senior in the movie might just have repercussions with Bush Junior. Still, the reaction in Berlin means that it's a film that's going to make an impact. I'm glad to have been a small part of it.

PS "A man, a plan, a canal, Panama" is a famous palindrome. It reads the same forwards and backwards.