SAMIR PETER is frowning. The self-described “Liberace of Baghdad” has just learnt that Liberace is better remembered as a gay icon than as a pianist. He slugs Sean McAllister, the director of the BBC documentary The Liberace of Baghdad. “You said it,” says McAllister.

When they first sit down together, the two men make an unlikely pairing — the svelte Englishman and the woebegone Iraqi — but their rapport soon reflects the eight months they spent living in each other’s pocket in Baghdad where Peter — an apt surname for a Christian Arab — tickled the ivories in the hotel piano bar. That’s where they met, back in January 2004, when McAllister was on a three-week recce for the BBC’s Storyville strand.

After Saddam’s capture by American forces, Storyville’s commissioning editor Nick Fraser was interested in a post-Saddam piece that would go behind the scenes to see how ordinary Iraqis live. McAllister, who earned kudos for the 1998 documentary The Minders, in which he turned his camera on the Iraqi government operatives who kept an eye on him during an assignment in the country, was the man for the job. But as the three weeks elapsed, McAllister was still looking for an angle.

“Each day I was going out looking for stories and each day I was coming back to the hotel and drinking wine with Samir,” he says. Which is when he realised that his story was sitting behind the piano.

To say that Samir Peter had led a rollercoaster existence would be giving too much credit to rollercoasters. None is so steep, none has such twists. The son of wealthy parents, he studied piano at a conservatory in Ancona, Italy, for three years until his money ran out. “I knew many Italian women,” he says, before embarking on a story about his first proper job as a “woman massager” and his time with a certain Signora Bianconi who took him in. A European tour ensued. He returned to Iraq shortly before Saddam took over leadership of the Baath Party and hence the country. Shortly after, Iraq declared war on Iran.

“I was at a party,” says Peter, recalling the first twist. “It was 6 o’clock in the morning.” Government agents, he says, were at the door, demanding that he accompany them to their headquarters. They forced him to “volunteer” for duty, and two weeks later he was in a Republican Army training camp. He served on the front and ending up stabbing to death an Iranian soldier, a deed he describes and indeed demonstrates in chilling detail.

On other details his memory is less precise: of the rest of his wartime service he refers vaguely to “friends” who engineered his exit from the army.

Returning to civilian life, he took up music instruction and started to build a name for himself as a concert pianist. His marriage to a doctor — she delivered one of Saddam’s daughters — yielded four children but little conjugal bliss. On the other hand, there was the Liberace reference.

“I had the same life,” Peter explains, “Many cars, many clothes. I had 350 shirts.” And many, many affairs.

“Liberace means glamourous,” McAllister adds helpfully. “You’d have liked to be called ‘the Chopin of Iraq’.”

McAllister, listening to similar exploits at the piano bar, was taken by this contradiction at the keyboard, a man who looks much older than his 56 years, perhaps because of rather than in spite of the wispy ponytail. Whether or not his stories were all true, the facts were plain: the Americans were in Baghdad, Saddam was deposed and Peter, who once earned $10,000 a month, was divorced, penniless and living in a basement room of the hotel, hoping for a visa to America. McAllister pitched the story — “his country has been liberated and now he’s leaving” — and got the green light.

At first, subject and film-maker had differing views of what the film would be about. Peter says he agreed to participate in the film because he thought it would be about his music. But, he says, as weeks turned to months, and McAllister and his camera were constant companions, he started to reveal more and more personal details, and the film — as he says — “took a political turn”.

For McAllister the change came when he met Peter’s daughter — although his wife had left him taking two of their now-adult children, the other two, a son, Fahdi, and a daughter, Sahar, had remained, living in the family house. “When I met Sahar, that’s when it got really interesting. Her conflict with Samir really interested me.”

Like many Iraqis, Sahar initially welcomed the invasion, but after so many months of occupation she turned against the liberators. “Americans only make promises,” she says in the film. McAllister recalls a scene left out of the film — remarkable considering that he shot 140 40-minute tapes — a moment when he asks Peter why his daughter loves Saddam. “Samir said, ‘She doesn’t love Saddam. She loves her country.’ It’s hard for people outside Iraq to understand what it means for the Americans to be on Iraqi soil. It was unthinkable to me, having been three times before.”

Does Peter feel the American presence is a bad thing? “No. They want to rebuild the country. But the people of Saddam are still there and they are trying to stop them. Anyone who works with them, they kill them. Americans offer jobs but they are afraid to work with them. They have spies in the Green Zone.”

McAllister has no doubt. “Look, I didn’t go to Baghdad with a Michael Moore-agenda to nail the Americans.” Although he was against the invasion, he says, he went “with an open mind to see what was going on, and for about four months I was the butt of the jokes of other journalists. I was saying: ‘They’re rebuilding. Give it time. Give it time.’ But the more you see, the more you completely, utterly despair. It is a catastrophe beyond f****** belief. From small examples to big examples . . .” He shakes his head. “It’s ten years in the making. This film will be topical for ten years.”

As for Peter’s future, at the time of going to press he’s been out of Iraq for one month. He has his American visa — to attend the Sundance Film Festival, where the film had its world premiere — but the next steps are tentative. He will meet up with his former wife and wait for Sahar and Fahdi to join him from Jordan.

As for the home in Baghdad? Peter shrugs. “I locked the doors.”

“His house-sitter was killed last week,” says McAllister. “On the street. Thirty years old, driving through a disturbance with the resistance. When the Americans get shot at, they just spray. A bullet hit him in the head and another hit the gas tank. He burnt to death. Thirty years old and two kids. The random danger of ordinary life.”

• The Liberace of Baghdad is on BBC Four tonight at 9pm