The settlement is between International Military Services Ltd, the state-owned company used by Britain's Defense Ministry that concluded the Chieftain deals in the 1970s, and Iran's Ministry of Defense.
Britain's The Independent newspaper noted that the settlement ""will bring to an end one of the more tortuous and murky sagas in that most opaque and scandal-riddled area of international affairs -- nation-to-nation arms deals.""
In the 1970s, the shah's government was favored by the United States and Britain as a vital bulwark against Soviet expansion to the strategic oil-rich Persian Gulf.
From 1971-76, his government ordered 1,500 Chieftains and 250 FV2404 armored repair vehicles, which retrieve damaged tanks from the battlefield, all manufactured by the Leyland Co. and Britain's state-owned Royal Ordnance Factories.
At that time, the FV4030/1 Chieftain was Britain's primary main battle tank. When it was unveiled in 1967 it had the most powerful main gun of any tank in the world -- the 120mm L11A5 rifled gun that could fire eight rounds a minute -- and the heaviest armor.
The contracts were worth 650 million pounds, today worth around $1.04 billion, and were paid in full in advance from the shah's treasury, then overflowing thanks to Iran's oil wealth.
Those funds were crucial in keeping Britain's defense industry going at a time of slumping sales.
But by the time the shah was toppled in January 1979 and went into exile, Britain had delivered 187 of the 55-ton FV4030/1 Chieftains, which the Iranians dubbed Shir-1. The British halted deliveries to what was deemed a hostile government in Iran after the U.S. Embassy in Tehran was stormed on Nov. 4, 1979.
Fifty-three U.S. diplomats and others were held hostage for 444 days, wrecking any prospect of the Chieftain deal being revived.
Iran demanded Britain return money paid for the undelivered tanks. London refused.