The date for the battle was finally set for 25th September 1915 with a feint attack to confuse the German commanders being made at Bellewaerde to the east of Ieper in Belgium.
It had been noted at Aubers and Festubert earlier in the year that the only guns capable of destroying the solid German defences were those of the heaviest calibre. To this end every suitable artillery piece available was gathered and just over a hundred would be used (the French would use four times that number at Vimy).
On the 21st the British artillery commenced its four day preparatory bombardment working to a carefully calculated rate of expenditure. This first phase would use two-thirds of the allocated munitions. The remainder was allotted between two days of battle and four days of consolidation.
It was taken as accepted that the weight of ammunition available for each metre of front was not sufficient to subdue the defences — thus, another reason why gas was considered essential.
The paucity of munitions for the battle is best highlighted by a comparison between Loos 1915 and Messines 1917. At the former the allotted rounds were : 35,000 of heavy and 500,000 for the field batteries. Less than two years later the figures were : 941,795 heavy and 2,619,745 of field.
On the eve of battle, Captain Ernie Gold RFC, Haig’s weatherman finally gave a positive forecast for the wind, it was up to Haig to make his decision as to which plan he was going with.
At 0500 hours Haig was standing outside his headquarters at the Château of Hinges. The night was still and Haig asked his ADC Major Alan Fletcher (17th Lancers) to light a cigarette and the pair of them watched the smoke drifting away towards the German positions. At that moment Haig chose to go with the gas.
At 0550 hours the gas was released followed, ten minutes later, by a smoke screen and at 0630 hours the First Army climbed out of its trenches and attacked the German lines.
The British were wearing rudimentary smoke hoods which basically consisted of a hood with eye holes — they were very uncomfortable to wear and made breathing difficult. Many soldiers decided to take the chance with the gas rather than the incapacitating gas mask.
The two original crassier can perhaps be made out at the base of the plateau
The front ran diagonally from the left towards the Loos Memorial (The location of the German redoubt); top centre
Lt General Sir Henry Rawlinson’s IV Corps was responsible for the southern half of the battlefield.
The 47th (London) Division had the task of attacking towards the Double Crassier a huge mound which dominated the main Béthune – Lens Road. They would then form a defensive flank.
The two great crassiers that you can see today are far higher than those of 1915.
The original war-time crassiers can only really be seen from the modern day plateau
into which they would have run.
To their left the 15th (Scottish) Division would attack Loos village and the ridge behind it, known as Hill 70. 1st Division, on the southern side of the Vermelles – Hulluch Road had the Bois Carré and the Lone Tree in front of them. Both Divisions were seeking to reach the Lens – La Bassée Road.
The northern half of the battlefield between the Hulluch Road and the junction with the Indian Corps (just on the far side of Givenchy) was occupied by I Corps commanded by Lt General Hubert Gough.
2nd Division, astride the La Bassée canal, would carry out a pre-battle assault with mines under the German lines on the northern side of the canal before participating in the main offensive. The 9th (Scottish) Division were required to capture the Hohenzollern Redoubt and progress towards the Lens Road with 7th Division on their right, in contact with IV Corps.