A foul smell hanging over southern England is being blamed on easterly winds bringing either farming or industrial smells across the Channel. Labelled "Euro-whiff" by the Met Office, the source of the smell - alternately described as sulphur and manure - is under investigation.
Sarah Holland from the Met Office said it has had dozens of calls from the public looking for information.
She said the smell had been detected as far west as Devon.
"Basically, over the last few days, we've had fresh, strong winds from an easterly direction," said Miss Holland. "As a result some of our air is coming from continental Europe."
'Not-so-fresh air'
Miss Holland said while members of Met Office staff were trying to trace the exact source of the "apparent atmospheric aroma", the likely explanation was either agricultural or industrial works in western Europe.
"Normally, our winds are westerly, coming off the Atlantic Ocean, which bring little or no pollution with them."
Some of the strongest smells have been reported in Reading and Basingstoke, with other reports of a stench in East Anglia and parts of Suffolk.
BBC News website readers have reported a range of sulphur-like smells hanging over areas across the London.
Thames Water told the BBC the smell was not related to water or sewage works.