<P> The British expressed outrage at Germany's use of poison gas at Ypres but responded by developing their own gas warfare capability . The commander of II Corps, Lieutenant General Sir Charles Ferguson, said of gas: </P> <P> It is a cowardly form of warfare which does not commend itself to me or other English soldiers...We cannot win this war unless we kill or incapacitate more of our enemies than they do of us, and if this can only be done by our copying the enemy in his choice of weapons, we must not refuse to do so . </P> <P> The first use of gas by the British was at the Battle of Loos, 25 September 1915, but the attempt was a disaster . Chlorine, codenamed Red Star, was the agent to be used (140 tons arrayed in 5,100 cylinders), and the attack was dependent on a favorable wind . However, on this occasion the wind proved fickle, and the gas either lingered in no man's land or, in places, blew back on the British trenches . This debacle was compounded when the gas could not be released from all the British canisters because the wrong turning keys were sent with them . Subsequent retaliatory German shelling hit some of those unused full cylinders, releasing more gas among the British troops . Exacerbating the situation were the primitive flannel gas masks distributed to the British . The masks got hot, and the small eye - pieces misted over, reducing visibility . Some of the troops lifted the masks to get some fresh air, causing them to be gassed . </P> <P> The deficiencies of chlorine were overcome with the introduction of phosgene, which was prepared by a group of French chemists led by Victor Grignard and first used by France in 1915 . Colourless and having an odor likened to "mouldy hay," phosgene was difficult to detect, making it a more effective weapon . Although phosgene was sometimes used on its own, it was more often used mixed with an equal volume of chlorine, with the chlorine helping to spread the denser phosgene . The Allies called this combination White Star after the marking painted on shells containing the mixture . </P>

When did the british first use gas in ww1