A massive leak of Mercaptan gas additive from a plant near Paris is now drifting across Southern England.
The chemical factory sprung the leak of the harmless cloud of gas yesterday.
Mercaptanis is a stenching agent that is put into domestic gas supplies to indicate that there may be a gas leak of some kind.
The French plant makes industrial lubricants and paint and said work is underway to contain the fumes , although the process could take hours or even days to complete.