A cloud of gas smelling of sweat and rotten eggs has leaked out of a chemicals factory in northern France and made its way across the English Channel, wafting as far as London.
Reuters reports the leak of harmless gas occurred on Monday at a Lubrizol France plant 120km northwest of Paris.
Strong winds blew the invisible gas over France and into England over the following 24 hours, with emergency services in London warning residents to keep their doors and windows closed.
Lubrizol manufactures lubricants and paints, and said the gas was used as an additive to natural gas to help detect leaks.
Reuters reports the cause of the leak is still unknown and the company is working to fix the problem.
Earlier this week the Paris police department issued a statement advising locals that while the gas was harmless it smelt of “sweat, garlic and rotten eggs”.