LONDON, May 18 (JTA) — A British Customs undercover operation resulted in the conviction of an agent for Iran’s nuclear weapons program. Ali Asghar Manzarpour, 37, an aerospace engineering student, was sentenced last week to nine months in jail for attempting to illegally export three-quarters of a ton of super-strength steel. The material was believed to have been destined for the construction of centrifuges that are used to enrich uranium for nuclear warheads. His conviction came as the world reacted strongly to India’s detonation of at least five nuclear devices in underground tests. The Iranian plan involving Manzarpour was foiled two years ago, when the first shipment of a $400,000 order for the steel arrived at London’s Heathrow and Gatwick airports from the United States. It was considered unusual that the consignment was flown at great expense, rather than shipped across the Atlantic, raising suspicions that the Iranians were desperate for the material. Manzarpour, who had been under surveillance for two years, was arrested in March 1996 as the steel was being loaded on to trucks, which were to transport them to Austria before being flown to Iran. He had set up an export-import company, Eurotrade, which initially dealt in men’s suits and transistor parts before moving into the fields of capacitors and circuit boards. The court was told that Manzarpour, who settled in Britain in 1980, was initially approached by experts at the Ya-Mahdi missile base near Tehran and an order was later placed by the Iranian Defense Ministry. He was paid $350,000 in advance to acquire the steel and was to a similar sum to be paid on completion of the contract. Using his wife’s maiden name, he ordered the material from Teledyne All Vac, a company in South Carolina. British Customs sources said they believed Manzarpour had been working with the Iranian government for at least a decade.