Margaret Thatcher's government was reluctant to press for an international ban on Iraqi dictator Saddam Hussein acquiring chemical weapons amid fears any criticism could rebound on the UK, according to newly released files.
Foreign Office papers released by the National Archives at Kew show that in early 1983 officials received intelligence from the Americans suggesting that mustard gas was being manufactured at a pesticide plant at Samarra to the north of Baghdad.
However, officials were concerned to learn that the Indian contractor which built the factory had acquired some of the equipment from a British company which was unaware of the Iraqis' true intentions.
While there was some discussion within the Foreign Office on trying to prevent Iraq acquiring a chemical weapons (CW) capability, officials noted that it could prove difficult as they were not banned under international treaties, even though their use was prohibited under the Geneva Protocols.
"The Iraqis could therefore legitimately say, as do the United States, that they need CW as a deterrent," a Foreign Office paper noted.
"A move to ban CW sales to Iraq would therefore look very discriminatory unless we could show that Iraq had breached, or intended to breach the Geneva Protocol."
But there was also, the paper acknowledged, another concern closer to home.
"Caution may be in order, since our own trade in CS gas has not escaped criticism. (The Russians claim that our use of CW in Northern Ireland contravened the Geneva Protocol)," the paper said.
"Another relevant factor is that a British company, Weir Pumps, has apparently supplied pumps to the Samarra factory under the impression that they were for use in making pesticides."
Nevertheless, officials agreed there should be an approach to "our closest allies" with a view to trying "at least to slow down, and perhaps even to frustrate Iraqi ambitions in this field".