You could be forgiven for thinking that the first use of gas on a massive scale would come as a surprise to the Allies and yet it shouldn’t have done.
All the warning signs were there — including the fact that the French had themselves been deploying tear gas from the very outset of the war.
Despite the Germans best efforts to keep their preparations secret it was impossible to keep everything under a closed lid. The soldiers were being equipped with makeshift gas masks, or had seen the installation of the gas cylinders.
On the 14th April 1915 a deserter from Reserve Infantry Regiment Nr 234 made his way into the French lines at Langemark. According to him a gas attack had been prepared for the night of the 15/16th April and would be signalled by the firing of three red rockets.
This signal would announce the opening of 50kg bottles of gas, grouped in batteries of twenty, along the front line. Each of these batteries was being supervised by five pioneers from either the 35th or 36th Pioneer Regiments.
The soldier even handed over his own cloth mask telling his interrogators that everybody in the front line had been issued with them and had been warned that everything depended on the weather. The attack would be postponed if necessary.
In passing the information over to the British the local French commander, Général Putz commented that he did not believe the information from the deserter because he had given such precise details of the German front line organisation. The soldier had to be a German plant.
In addition to this deserter’s information, Belgian spies in Gent reported on the 15th that the Germans had ordered 20,000 compresses 9cm x 14cm. These would be dipped in some suitable liquid to protect the wearer from the effects of gas.
A number of captured German soldiers were all noted to be carrying these compresses and all stated that they were to protect them from asphyxiating gas. Many had received training as to how the gas cylinders would work.
On the 16th April, No 6 Squadron, Royal Flying Corps carried out a number of missions over the German lines but could see nothing suspicious. The feeling was that the Germans had decided to engage in some grand scale psychological warfare.
Both sides still believed in a short war. Their respective Spring campaign was going to win, so anything that perturbed the enemy was obviously going to be an advantage.
Still, the evidence was piling in. That same day, the 16th April, the British took possession of Hill 60 near Zillebeke. This was in the area that the Germans had originally considered for their gas attack (When the wind refused to turn favourable they decided on the subsequent location against the French at Langemark).
During the attack the British noticed that there was a very unusual smell in the atmosphere and German officers who had been taken prisoner explained that there were gas cylinders out in no man’s land.
A sergeant was sent out with a patrol to carry out a search and uncovered dozens of the cylinders. His report would appear to have become lost in the administration.
The following day the Germans announced to the press that the British had carried out an attack to the east of Ieper using asphyxiating gas. The British countered that this was the smell of the Lyddite explosive in the shells (The Boers had made the same accusation against the British during their war against the Empire).
Over the next few days German radio messages were intercepted from a certain Haber who was constantly worried about the weather and changes in the wind direction.