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Thirty-five years ago this week, Iraq invaded Iran and what has been described as the 20th Century's longest conventional war began. Both sides suffered terrible casualties but they had different motives for fighting and now, looking back, two soldiers see their experiences in a very different light.

How many soldiers go into battle with a smile on their face?

How many have fond memories of a war in which perhaps a million people were killed?

Meet Mehdi Talati. Aged just 15, he took up arms after Saddam Hussein's Iraqi forces invaded his homeland, Iran, 35 years ago.

The attack, on 22 September 1980, sparked the Iran-Iraq War, which did not end for eight years. Saddam had promised a whirlwind victory, but he had reckoned without the intense religious devotion of many Iranians toward their new revolutionary leader, Ayatollah Khomeini.

"We loved Imam Khomeini, and when he gave the order to defend the country, we were happy to answer his call," says Mehdi. "All my generation went - and I think we went with joy."

Mehdi joined the basij, a volunteer militia dedicated to upholding Iran's Islamic revolution. Most were, like him, young and inexperienced. They were also poorly equipped. Yet he speaks about the fight with clear delight.

"We were just young kids with Kalashnikovs and grenades - which we didn't even dare to use at first because a lot of us were afraid to throw them! We didn't even have bread! The logistics were terrible. But that obligation [to Khomeini] was so strong it covered everything."

It was a different story on the Iraqi side.

Image copyright AFP

To begin with, the Iraqis made progress, occupying the Iranian port of Khorramshahr. But although Saddam Hussein's elite Republican Guard were as loyal as the basijis, many of his other troops were conscripts, and went to war with less enthusiasm. It is perhaps significant that few of them seem to relish describing their experiences today, and those who will talk often prefer to remain anonymous.

One of them is "Adnan", now a journalist living overseas, who was drafted into the army in 1981.

I couldn't watch, I just heard the sound of the shots - it was very bad Adnan, former Iraqi conscript

"I was enrolled in training. It was very harsh for all the company. I remember the trainers - holding batons. Those trainers hit you - on your head, on your shoulders, on your chest. I felt from the beginning they are putting down the morale of the army. Tell me, how can a soldier fight when his morale is low?"

But they did fight. It's thought that some 250,000 Iraqis could have lost their lives in the war. And those who wouldn't engage in the slaughter of Iranians were dealt with brutally.

"The execution… You know I can't erase it from my memory," recalls Adnan.

"I was sitting with my colleagues, and there was a fuss outside! People coming, coming, coming! And I saw two military ambulances arrive.

"I asked my colleague what was going on. He told me there are two or three soldiers - they are preparing them to be executed. The excuse was that they had left their position. I couldn't watch. I just heard the sound of the shots. It was very bad. Really very bad."

Image copyright AFP

Breaking off suddenly, Adnan taps the desk restlessly, looking far into the distance.

"Now, when I remember, I want to cry," he says. "This absurd war that we were sent to - it was an inferno. Really, an inferno."

It was a very elegant moment - I would rather die in that moment than live after the war Mehdi, Iranian volunteer

In 1982, Saddam announced a withdrawal from the areas he had invaded. He had spread his forces too thinly and the basijis' self-sacrifice helped repel them. Even so there was to be no peace for another six years. The two sides entrenched and fought battles often reminiscent of World War One in their futility, with massive slaughter for very small territorial gain.

"They asked our company to go to Khorramshahr, and from our company only five people managed to cross Shatt-al-Arab waterway bordering Iraq with Iran," says Adnan. "The others were either killed or taken prisoner. Only five people came back, and the officials started to re-form a new company under the same name."

The Iranians, who were usually less well equipped, suffered even more deaths than the Iraqis. After the Islamic revolution, and the seizure of American diplomats as hostages, the world had punished Tehran with an arms embargo. The biggest asset its young volunteers had was their sheer number, and they advanced in surprise "human wave" attacks - often straight into machine-gun fire from the Iraqi trenches.

"You're getting shot at, killed. Sometimes they cannot find your body. It's in pieces. And then you see that it's an unequal war - all you have is yourselves and the other side have everything - bunkers, artillery, air force," says Mehdi, who once volunteered to clear a path through a minefield by running across it.

Image caption Mehdi: "I think it was beautiful"

"When you do not have weaponry you have to break the enemy line with your body. Even the barbed wire - sometimes we couldn't cut it, so we would throw ourselves upon it with our bodies, so others could pass over us. Our casualties went up and up. Sometimes 70, 80, 90% of our units were destroyed."

Today Mehdi lives as an academic in the West, but he still has battle scars all over his body. His knee joints are plastic replacements, and a bullet still lodges deep within his hand.

Over the long years of the war, the basij improved its efficiency, evolving from a rag-tag militia into a battle-hardened force.

"The first time when I saw a grenade strike the earth I lay on the ground for several minutes, I was so afraid," says Mehdi.

"But in time hundreds of grenades were coming - and I didn't mind. You adapt, and get used to war. You start to recognise which bullet is passing you, and which bullet is in front of you. You become more professional. And some basijis were really good by the end of the war."

But by August 1988, when Ayatollah Khomeini was persuaded to accept a UN-brokered ceasefire, the Iranian death toll was anywhere from 300,000 to one million.

Yet for the devout basijis, death held little horror. They sincerely believed they would become martyrs, with their sins forgiven and paradise assured in the afterlife. And they felt that on Earth, their theological revolution, under attack from the outside world, was also something well worth dying for.

That resolve says Mehdi, made their war not only bearable, but actually desirable.

"I think it was beautiful," he says. "It was a very elegant moment. I would rather die in that moment than live after the war.

"It was so nice."

The War the World Needs to Remember airs on the BBC World Service on Saturday 26 September - click here for transmission times, or catch up later on the BBC iPlayer

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