HAMPSHIRE has been engulfed by a foul-smelling gas cloud which wafted over from France, triggering thousands of calls to the emergency services and the National Grid.
Peopleacross the county first reported the smell after a discharge of the gas mercaptan from a factory in the northern city of Rouen drifted across the English Channel.
By the afternoon the unpleasant aroma - similar to 'rotten eggs' - had spread further up the country, with reports coming in from as far north as Northampton.
The National Grid, which would normally deal with up to 10,000 calls countrywide in a day, was inundated with more than 100,000 calls by 2pm. A spokesman said it was an ''unprecedented'' volume.
Mercaptan is added to municipal gas to alert people to gas leaks, among other uses, but is not toxic and poses no harm to the public, according to the Health Protection Agency (HPA).
It said the gas had diluted since entering the air over England, and, although it may cause some people to feel slightly nauseous, it will dispel naturally.
The HPA said: ''The smell drifting over southern England today poses no risk to public health. The odour, which is similar to rotten eggs, has been noticed by people mainly in Kent, East and West Sussex and some parts of Surrey.
''It is caused by a particularly smelly chemical that is added to odourless natural gas to give that its characteristic smell. The chemical leaked from a factory in Rouen, France, yesterday and has blown across the Channel overnight.
''It is not toxic and has also been diluted before entering the air over England, so people should be reassured it will cause no harm. It is an unpleasant odour which may cause some people to feel slightly nauseous but it will dispel naturally.''
According to the French interior ministry, the factory at the centre of the leak is owned by Lubrizol, a subsidiary of investor Warren Buffet's Berkshire Hathaway group.
The company's operations director Pierre-Jean Payrouse told French radio that they were trying to contain the problem but the cause of it was unknown.
He told RTL radio: ''It's not so much a leak as a product that has decomposed, which smells very bad and which is escaping. An investigation is under way but our priority is to deal with the problem.''
The stench provoked mirth on Twitter.
London Fire Brigade tweeted: ''We've been called to 25 gas incidents since 10.30am. The rotten egg smell is coming from France but has no risk to public £zutalors.''
In Kent, residents were urged by the fire brigade to keep doors and windows closed, while in Hampshire, the fire and rescue service received more than 20 calls.
Hampshire Fire and Rescue say they have also received more than 20 calls, mainly from the Portsmouth area, but as far north as Basingstoke and as far west as Ringwood.
Group Manager Tony Deacon said: "Our control room has dealt with a number of calls reporting the unpleasant gas smell.
"We want to reassure the public that the gas presents no threat to health and is completely harmless."
Stella Fowler, 73, from Brook Road, Bitterne, Southampton, said she noticed a stink when she went into her garden.
She said: “It smells like sulphur, like rotting eggs. It’s horrible.
“I noticed it in the garden and I checked it wasn’t coming from my gas flue – but it wasn’t.”
Anyone concerned about a gas emergency in their home or building should still call the National Gas Emergency Number on 0800 111 999.
Have you smelt the whiff? If so, contact Bethan Phillips on 023 8042 4520.