The first World War came back to haunt the residents of a small village between Lens and Arras in northern France yesterday.
Between midday and nightfall, 13,000 people from Vimy and neighbouring hamlets, including schoolchildren and old people in a retirement home, were evacuated from the killing field where the Canadian army triumphed over German troops entrenched at Vimy Ridge at Easter, 1917.
Panic had spread through the Nord and Pas-de-Calais departments on Thursday night, when locals heard that 130 coaches were wending their way towards them.
Hospital staff throughout the area were placed on alert and ordered not to leave for Easter holidays.
It was only a small jump from reports of "crisis cells" and "Parisian experts" to the conclusion that a nuclear accident must have occurred at the Gravelines power plant near Dunkirk.
But it was low-tech mustard gas, chlorine and phosgene - not water-cooled nuclear reactors - which brought the Interior Minister, Mr Daniel Vaillant, to Arras, cancelled the Troyes-Lens football match that was to have taken place today and made 13,000 people homeless at Easter.
Mr Vaillant's statement alluded to a recent study that provided "very worrying information on the deterioration of storage conditions" at the Vimy munitions dump, where 170 tonnes of first World War munitions were kept.
Nearly one third of these are what sappers call "leakers" - early chemical weapons for which, nearly a century after their manufacture, there is still no easy disposal.
The "leakers" are usually kept in water to prevent toxic gases mixing with air.
Riot police and 350 teams of firemen were dispatched to Vimy, where weapons are being deactivated and loaded into refrigeration trucks for transport to an army camp at Suippes, 200 km to the east. The process is expected to take 10 days.
Five hundred tonnes of old munitions are still found in France every year, and the Pasde-Calais prefecture receives 25 phone calls a day during ploughing season.
Experts say it will take centuries for all the shells to be found. Vimy was chosen in 1967 as a "temporary" storage site.
But the weapons were left in an open field surrounded by a rickety fence.
A campaign by environmentalists and French media forced the ministry of the interior to improve security and announce plans to move the depot in 1997. Two sappers were killed when a shell they were unloading at Vimy exploded at the end of 1999.
Fighting from water-logged fields in 1917, the Canadians stormed up the ridge - firing more than a million shells in the process - to dislodge German troops from Vimy Ridge. Two hundred thousand Canadians, British, French and German men died there.
The allies detonated huge mines below the German trenches and the blast was so powerful that it allegedly rattled the windows of Downing Street. The craters are still there, and the main German blockhouse now forms the centrepiece of the Canadian cemetery.
