Editing First day on the Somme (section)

===Anglo-French preparations===

====Aircraft====
For long-distance reconnaissance, bombing and attacks on {{lang|de|[[Luftstreitkräfte|Die Fliegertruppe]]}} (the Imperial German Flying Corps up to October, then {{lang|de|Deutsche Luftstreitkräfte}}, [German Air Force]) the [[No. 9 Wing RAF|9th (Headquarters) Wing]] of the [[Royal Flying Corps]] (RFC) was moved to the Somme front, with [[No. 21 Squadron RAF|21]], [[No. 27 Squadron RAF|27]], [[No. 60 Squadron RAF|60]] squadrons and part of 70 Squadron. The [[Fourth Army (United Kingdom)|Fourth Army]] had the support of [[IV Brigade RFC]], with two squadrons of the [[No. 14 Wing RAF|14th (Army) Wing]], four squadrons of the [[No. 3 Wing RAF|3rd Wing]] and 1 [[Kite balloon|1 Kite Balloon Squadron]], with a section for each corps. Corps squadrons, [[No. 3 Squadron RAF|3]], [[No. 4 Squadron RAF|4]], [[No. 9 Squadron RAF|9]] and [[No. 15 Squadron RAF|15]]  had {{nowrap|30 aircraft}} for counter-battery work and {{nowrap|13 aircraft}} for [[Patrolling#Aviation patrol types|contact-patrol]], where reconnaissance aircraft flew low over the battlefield to map the positions of British troops. Brigade headquarters had been ignorant of events and arrangements were made for the swift transmission of information forwards. There were {{nowrap|16 aircraft}} for trench reconnaissance, destructive bombardment and other duties and nine aircraft in reserve.{{sfn|Jones|2002|pp=147–148, 179–181}}

[[VII Corps (United Kingdom)|VII Corps]] (Lieutenant-General [[Thomas Snow (British Army officer)|Thomas Snow]]) in the [[Third Army (United Kingdom)|Third Army]] was given [[No. 8 Squadron RAF|8 Squadron]] with {{nowrap|18 aircraft}} and 5 Kite Balloon Section. On the Somme the RFC had {{nowrap|185 aircraft}} against the German 2nd Army aircraft establishment, which also had to face the French {{lang|fr|[[Aviation Militaire]]}} on either side of the Somme (the Anglo-French air effort considerably outnumbered the Germans until mid-July). Protection for corps aircraft was to be provided by standing patrols of pairs of aircraft and offensive sweeps by the two army squadrons.{{sfn|Jones|2002|pp=147–148}}{{efn|After 30 January 1916, each British army had a Royal Flying Corps brigade attached, which was divided into [[Wing (military aviation unit)|wings]], the corps wing with squadrons responsible for close reconnaissance, photography and artillery observation on the front of each corps and an army wing, which controlled the fighter squadrons and conducted long-range reconnaissance and bombing, using the aircraft types with the highest performance.{{sfn|Jones|2002|pp=147–148}}}} Bombing attacks were to be made on the railways behind the German front, with the main effort beginning on 1 July, to ensure that damage could not be repaired before the offensive. Troops, transport columns, supply dumps and headquarters behind the battlefront were to be attacked and the ammunition depots at [[Mons, Belgium|Mons]], [[Namur]] and [[Lille]] were to be specially attacked.{{sfn|Edmonds|1993|pp=268–269}} The French Sixth Army (General [[Émile Fayolle]]), had {{nowrap|201 aeroplanes.}}{{sfn|Philpott|2009|p=269}}

====Artillery====
[[File:60PounderBatteryContalmaison.jpg|upright=1.25|thumb|{{centre|[[BL 60-pounder gun|60-pounder]] gun battery}}]]
The British had substantially increased the amount of artillery on the Western Front after the Battle of Loos in late 1915 but the length of front to be bombarded on the Somme led to the preparatory bombardment being planned to last for five days. There had been a debate about the merits of a short [[hurricane bombardment]] but there were insufficient guns quickly to destroy German field defences and be certain that barbed wire was cut, given the dependence of the artillery on air observation and the uncertain weather.{{sfn|Edmonds|1993|pp=122–124}}{{efn|In 1916, despite improvisation and inexperience, British industry produced {{nowrap|33,507 machine-guns,}} {{nowrap|5,192 trench}} mortars with {{nowrap|6,500,000 rounds,}} {{cvt|127,000|LT}} of explosives and {{cvt|84,000|LT}} of propellants. [[Mills bomb]] production rose to {{nowrap|1,400,000 per}} week and the output of shells rose from {{nowrap|4,336,800 in}} the first quarter of 1916 to {{nowrap|20,888,400 in}} the final quarter, for an annual total of more than fifty million. On the Somme, {{cvt|148,000|LT}} of ammunition were expended from {{nowrap|24 June – 23 July}} and {{cvt|101,771|LT}} were landed in France.{{sfn|Edmonds|1993|p=124}} Some heavy guns and howitzers burst on firing, due to defective shells made from inferior steel with hairline cracks, through which the propellant discharge detonated the shell. The fuzes of [[BL 8-inch howitzer Mk VI – VIII|8-inch howitzers]] failed so often that the battlefield was littered with blinds (duds) and a remedy made the fuzes fall out. Many shells failed to explode due to deterioration of the explosive filling and many guns misfired due to poor quality barrels. The [[60-pounder]] guns averaged a premature explosion every {{nowrap|500 shrapnel}} rounds and [[4.5-inch howitzer]] shells exploded in the barrel or {{cvt|4|–|5|yd}} beyond the muzzle, the crews being nicknamed suicide clubs. Some propellants were not fully consumed on firing, requiring the barrel to be cleaned after each shot, which slowed the rate of fire. Some copper [[driving band]]s on [[18-pounder]] field gun shells were too hard, which reduced the accuracy of the gun; when high-explosive ammunition had been introduced late in 1915, premature detonations and bulges occurred, with a burst barrel every thousand shots. There was a shortage of buffer springs, replacements were sometimes worse than worn ones and spare parts for every mechanical device in the army were lacking. Some shells exuded explosive in the summer heat, flare fillings decomposed, phosphorus bombs went off spontaneously and the firing mechanism of the heavy trench mortars failed on 1 July. Stokes mortar ammunition was chronically unreliable until replaced by improved designs. Many Mills bombs and rifle grenades prematurely detonated or were duds and a make of rifle cartridge jammed in the breach after firing and had to be scrapped.{{sfn|Edmonds|1993|pp=122–124}}}}

The artillery had to cut barbed wire and neutralise German artillery with counter-battery fire. The British artillery fired more than {{nowrap|1.5 million}} shells during the preliminary bombardment, more than in the first year of the war. On 1 July, another {{nowrap|250,000 shells}} were fired; the guns could be heard on [[Hampstead Heath]], {{cvt|165|mi}} away. While this weight of bombardment was new for the British, it was common on the Western Front; at the [[Second Battle of Artois]] in May 1915, there had been a six-day preparatory bombardment with over {{nowrap|2.1 million}} shells. British shell production had increased since the [[shell scandal]] of 1915 but quality had been sacrificed for quantity.{{sfn|Prior|Wilson|2005|pp=62–63}} [[shrapnel shell|Shrapnel]] shells were virtually useless against entrenched positions and required accurate fuze settings to cut wire; very little high-explosive ammunition had been manufactured for field artillery.{{sfn|Farndale|1986|p=144}}{{efn|Field artillery: {{nowrap|808 [[Ordnance QF 18 pounder|18-pounder guns]]}} for wire-cutting with shrapnel and bombarding troops in the open, {{nowrap|202 [[QF 4.5 inch Howitzer|4.5-inch howitzers]]}}. Heavy artillery: {{nowrap|32 [[QF 4.7 inch Gun Mk I–IV|4.7-inch guns]]}} for counter-battery fire, {{nowrap|128 [[BL 60 pounder gun|60-pounder guns]]}} for counter-battery fire, {{nowrap|20 [[BL 6 inch Mk VII naval gun|6-inch guns]]}} for wire-cutting and counter-battery fire, {{nowrap|1 [[BL 9.2 inch Railway Gun|9.2-inch railway gun]]}}, {{nowrap|1 [[BL 12 inch Railway Gun|12-inch railway gun]]}}, {{nowrap|104 [[6 inch 26 cwt howitzer|6-inch howitzers]]}}, {{nowrap|64 [[BL 8-inch howitzer Mk I–V|8-inch howitzers]]}}, {{nowrap|60 [[BL 9.2 inch Howitzer|9.2-inch howitzers]]}}, {{nowrap|11 [[BL 12 inch Railway Howitzer|12-inch railway howitzers]]}}. Six [[BL 15 inch Howitzer|15-inch howitzers]], {{nowrap|288 [[2 inch Medium Mortar|2-inch medium mortars]]}} and {{nowrap|28 heavy}} trench mortars were reserved for wire cutting. The French supplied {{nowrap|60 [[Canon de 75 modèle 1897|75 mm guns]]}} (gas shell only), twenty-four 120 mm guns, sixteen 220 mm howitzers.{{sfn|Farndale|1986|p=144}}}} The French Sixth Army had {{nowrap|552 heavy}} guns and howitzers, with a much larger supply of high-explosive ammunition for field artillery and far more experienced personnel.{{sfn|Doughty|2005|p=292}}

====Cavalry====

[[File:British gas attack Somme June 1916 IWMQ 55066.jpg|thumb|{{centre|Aerial photograph of a British [[Chemical weapons in World War I|gas attack]] from Carnoy to Montauban, shortly before the Somme offensive.}}]]
In March, the two British cavalry corps were disbanded and the divisions distributed to the armies and the new Reserve Corps (General [[Hubert Gough]]). In June, the Reserve Corps was reinforced and became the [[Reserve Army (United Kingdom)|Reserve Army]]. The Reserve Army cavalry was to operate combined with infantry and artillery, ready to act as a "conveyor belt", to exploit a success by the Fourth Army, with the 25th Division in the lead followed by two cavalry divisions and then [[II Corps (United Kingdom)|II Corps]].{{sfn|Sheffield|2011|pp=166–167}} In mid-June, II Corps was transferred to the Fourth Army; the French Sixth Army contained four cavalry divisions.{{sfn|Philpott|2009|pp=166–167}}

In late June, favourable intelligence reports and the reduction of the French commitment for the Somme offensive led to a change of plan by the British. Should the German army collapse, the cavalry was to follow up, capture [[Bapaume]] and take post on the right flank, to provide a flank guard of all-arms detachments facing east, as the main body of cavalry and the infantry advanced northwards. The [[1st Cavalry Division (United Kingdom)|1st]], [[2nd Indian Cavalry Division|2nd (Indian)]] and [[3rd Cavalry Division (United Kingdom)|3rd Cavalry]] divisions were to assemble by zero hour {{cvt|5|mi}} west of [[Albert, Somme|Albert]] around [[Buire-sur-l'Ancre|Buire]], [[Bresle]], Bonny and [[La Neuville-lès-Bray|La Neuville]], ready to move forward or remain and then return to billets behind [[Amiens]] depending on events.{{sfn|Edmonds|1993|pp=266–267}}

====Infantry====
A BEF manual published on 8 May 1916 (SS 109, ''Training of Divisions For Offensive Action''), described successions of lines to add driving power to the attack, to reach the objective with the capacity to consolidate the captured ground against counter-attack.{{sfn|Griffith|1996|p=56}}{{efn|[[Paddy Griffith]] criticised [[James Edward Edmonds|James Edmonds]], the official historian, for assuming that line-formations were rigid, not capable of [[Infiltration tactics|infiltration]] and inferior to small groups or blobs, despite them being complementary forms which were used throughout the war.{{sfn|Griffith|1996|p=56}}}} In the Fourth Army Tactical Notes of May 1916, battalions were allowed to attack on a front of {{nowrap|2–4 platoons}} in {{nowrap|8–4 waves}} about {{cvt|100|yd}} apart. Supporting lines were to pass through the leading ones, to avoid excessive demands on the energy and ability of individual soldiers. Weight of numbers was rejected as a tactic; each platoon was to carry half the burden of a brigade attack for a few minutes, before being relieved by a fresh wave. Platoons were divided into functions, fighting, mopping-up, support and carrying; the fighting platoons were to press on as the moppers-up secured the ground behind them. Support and carrying platoons could pick their way through artillery barrages with the tools and weapons needed to consolidate and defeat German counter-attacks.{{sfn|Griffith|1996|pp=56–57}}

Some troops in carrying platoons had about {{cvt|66|lb}} of equipment and tools, whereas troops in the advanced platoons carried a [[rifle]], [[bayonet]], {{nowrap|170 rounds}} of ammunition, iron ration (an emergency ration of preserved food, tea, sugar and salt), two [[grenade]]s, pick, shovel or [[entrenching tool]], four empty sandbags, two [[PH helmet|gas helmets]], wire cutters, a [[smoke candle]] and a water-bottle.{{sfn|Edmonds|Wynne|2010|pp=196–211}}{{efn|In the 56th (1/1st London) Division, each man carried {{nowrap|200 rounds}} of small-arms ammunition, a waterproof sheet, haversack, iron ration and the day's ration, two or three sandbags, two gas helmets and a "proportion of wire-cutters, bill-hooks and tools".{{sfn|Dudley Ward|2001|p=31}}}} In the French army, the experience of 1915 showed that despite the power of French bombardments, infantry would enter a chaotic environment, full of German pockets of resistance and individuals who had been by-passed. By mid-1916 much of the French infantry in the Sixth Army were specialist rifle-and-bayonet men, bombers, rifle grenadiers or light machine-gun crews. Attacking waves were spread wider and companies trained to manoeuvre in small groups, to get behind surviving German defences, as {{lang|fr|Nettoyeurs de Tranchées}} (trench cleaners) armed with hand-grenades and revolvers, searched captured ground for stray Germans and hidden machine-gunners, although such methods did not come into general use until later in the year.{{sfn|Philpott|2009|pp=149–150}}

====Mining====
{{see also|Mines on the first day of the Somme}}

[[File:Battle of the Somme 1916 - Lochnagar mine, La Boisselle.jpg|thumb|{{centre|Diagram of the [[Lochnagar mine]]}}]]
The chalk soil of the Somme was ideal for tunnelling and the British inherited a number of mine workings from the French army.{{sfn|Edmonds|1993|p=38}} The [[Tunnelling companies of the Royal Engineers|British tunnelling companies]] placed [[Mines on the first day of the Somme|19 mines]] beneath the German front positions and prepared [[Russian sap]]s from the British front line into [[no man's land]], to be opened at [[Zero Hour (military designation)|zero hour]] and allow the infantry to attack the German positions from a comparatively short distance.{{sfn|Jones|2010|p=115}} The mines on the Somme were the largest yet in the war. The mines were to destroy the German defences and to provide shelter in no man's land for the advancing infantry. Eight large and eleven small [[Mining (military)|mines]] were prepared for the first day of the battle; three large mines of up to {{cvt|24|LT}} and seven mines around {{cvt|5000|lb|LT}}.{{sfn|Edmonds|1993|pp=286–287}}

When the mines were blown, infantry were to rush forward to seize the craters; the largest mines, each containing {{cvt|24|LT}} of [[ammonal]], were on either side of the Albert–Bapaume road near [[La Boisselle]], [[Y Sap mine]] north of the road and [[Lochnagar mine]] to the south. H3, the other large mine was planted under [[Hawthorn Ridge Redoubt]] near [[Beaumont Hamel]], containing {{cvt|18|LT}} of explosive. The mines were to be detonated at {{nowrap|7:28 a.m.,}} two minutes before zero hour, except for the Hawthorn Ridge mine, which was to be sprung at {{nowrap|7:20 a.m.}} (The small mine at [[Kasino Point]] was mistimed and blown after the infantry attack had commenced.){{sfn|Edmonds|1993|pp=329, 331, 348–349, 374–375, 380, 429–430, 439}}

====Supply====
{|class="wikitable" align=right style="margin:0 0 1em 1em"
|+<small>'''BEF railway tonnage (1916)'''</small>{{sfn|Henniker|2009|p=179}}
|-
! Month
! [[long ton|LT]]
|-
|Jan||align="right"|2,484
|-
|Feb||align="right"|2,535
|-
|Mar||align="right"|2,877
|-
|Apr||align="right"|3,121
|-
|May||align="right"|3,391
|-
|Jun||align="right"|4,265
|-
|Jul||align="right"|4,478
|-
|Aug||align="right"|4,804
|-
|Sept||align="right"|4,913
|-
|Oct||align="right"|5,324
|-
|Nov||align="right"|5,107
|-
|Dec||align="right"|5,202
|}
From 1 January to 3 July 1916 the BEF was reinforced by {{nowrap|17 divisions}} and the number of heavy guns increased from {{nowrap|324 to 714.}} The new divisions needed {{frac|51|1|2}} supply trains a week to meet daily needs and a large number of extra trains to transport heavy artillery ammunition. Until mid-June, ammunition supply for the BEF needed {{nowrap|5–12 trains}} per week, then rose to 45 to 90 trains a week, to deliver {{cvt|148000|LT}} of munitions. Ammunition expenditure became a concern by 12 July but deliveries to the area behind the Fourth Army kept pace, although transport from railheads to the guns was not always maintained. In the weeks before 1 July, an extra seven trains a day were sufficient to deliver ammunition.{{sfn|Brown|1996|pp=159–162}} In the rear of the Fourth Army, huge encampments were built for troops, horses, artillery and workshops, dumps were filled with equipment, reservoirs and pipelines.{{sfn|Philpott|2009|pp=157–160}}

Power stations, light railways roads and telephone networks were constructed and more than {{cvt|2000000|impgal}} of petrol per month was delivered for the lorry fleet, moving supplies up to {{cvt|3|mi}} from railheads to the front line. A million [[Brodie helmet]]s were delivered between January and June. In the [[37th Division (United Kingdom)|37th Division]] area, {{nowrap|91,420 man-hours}} were needed to dig {{cvt|6|km|order=flip}} of trenches, jumping-off points, command-posts, dug-outs, machine-gun emplacements and ammunition stores, for wiring and for maintenance. In the French Sixth Army sector, one railway line from Amiens led to [[Bray-sur-Somme]] on the north bank but on the south bank there were no rail lines; road convoys carried supplies from Amiens to [[Foucaucourt-en-Santerre]].{{sfn|Philpott|2009|pp=157–160}}

====Intelligence====

{{see also|Brusilov Offensive}}

In March and April, eight German divisions were believed to be in reserve opposite the British from the Somme to the North Sea coast. Divisions in reserve behind the [[4th Army (German Empire)|4th Army]] were then moved south to Artois in the 6th Army area. From 4 to 14 June, the success of the [[Brusilov Offensive]] became apparent and agent reports showed increased railway movement from [[Belgium]] to [[Germany]]. The final BEF military intelligence estimate before 1 July had {{nowrap|32 German}} battalions opposite the Fourth Army and {{nowrap|65 battalions}} in reserve or close enough to reach the battlefield in the first week. Five of the seven German divisions in reserve had been engaged at Verdun and some divisions had been transferred from France to the [[Eastern Front (World War I)|Eastern Front]]. Men of the 1916 conscription class were appearing among German [[prisoners of war]], suggesting that the German army had been weakened and that the British could break down the German front line and force a battle of manoeuvre on the defenders. In late June, the British part of the Somme plan was amended, rapidly to capture Bapaume and envelop the German defences northwards to [[Arras]], rather than southwards to [[Péronne, Somme|Péronne]]. An increase in the number of trains moving from Germany to Belgium was discovered but the quality of German troops opposite the British was thought to have been much reduced. The true number of German divisions in reserve in France was ten, with six opposite the British, double the number the British knew about. Reports of work continuing on the German defences opposite the Fourth Army in March and April led the planners to adopt a less optimistic view, particularly due to the news about very deep shell-proof shelters being dug under German front trenches, which were far less vulnerable to bombardment.{{sfn|Beach|2004|pp=160–163}}