The Department for Business, Innovation and Skills (BIS) granted a number of licences to specialist firms allowing them to deliver sodium fluoride to Syria before the current conflict and European Union (EU) sanctions.
The licences allowed the sale of the chemical for commercial use in cosmetics and healthcare products, and there is "no evidence that the chemicals were used in weapons programmes", a spokeswoman for BIS was quoted as saying by the London Evening Standard.
Export licences for potassium fluoride and sodium fluoride were granted even months after the bloody civil war in the middle-eastern country began.
Sarin, a nerve gas that is hundreds of times deadlier than cyanide, is considered one of the world's most dangerous chemical warfare agents. It works on the nervous system, over-stimulating muscles and vital organs, and a single drop can be lethal in minutes.
The chemical export licences were granted by Business Secretary Vince Cable's Department for Business, Innovation and Skills last January - 10 months after the Syrian uprising began.
They were revoked six months later, when the European Union imposed tough sanctions on Assad's regime.
However, a spokesman for the Department of Business, Innovation and Skills (BIS) defended the sale of the chemical to Syria, saying the amount was "commensurate with the stated end use in the production of cosmetics and there was no reason to link them with Syria's chemical weapons program."
