A metal detectorist walking through Farlington Marshes near Portsmouth encountered an unusual type of UXO. Suspecting the devices were hazardous, he called the Police.
Royal Navy personnel identified the UXO as multiple chemical-filled mortar bombs. EOD divers from Portsmouth naval base prepared the munitions for delivery to an MOD chemical weapons facility.
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The specific ammunition model was not confirmed. They could have been MK I 4.2 inch chemical (Mustard Gas) mortar bombs.
Why Farlington Marshes?
One of the more likely reasons is coastal defence during WW2. In 1940, the prospect of a German invasion of southern England was very real. As such, a plan was drawn up to equip coastal defence forces with Mustard Gas munitions.
Alternatively, isolated marshland would have provided an ideal location for a mortar range. It is possible therefore that Farlington Marshes were requisitioned for such use. However, as military grade gas drifts with the wind, urban Farlington surely would have been considered too close.
British WW1 Chemical Weapons Use
In retaliation for the use of Chlorine by Germany against British troops in April 1915, British forces deployed chlorine themselves for the first time during the Battle of Loos on 25th September 1915.
By 1918, poison gas use had become widespread on both sides with a quarter of artillery shells filled with gas. Britain had produced around 25,400 tons of toxic chemicals by war’s end. Britain used a range of poison gases during WW1, originally Chlorine and later Phosgene, Diphosgene and Mustard Gas.