175th Tunnelling Company
The 175th Tunnelling Company was a Royal Engineers unit that conducted underground mining, counter-mining, construction and demolition operations on the Western Front during the First World War.
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Overview
The 175th Tunnelling Company was one of the specialist tunnelling units created by the British Army during the First World War. It belonged to the Royal Engineers and operated primarily on the Western Front, where underground warfare became an important part of the struggle between British and German forces. Its work included offensive mining beneath enemy positions, defensive counter-mining, underground listening and access galleries, troop shelters, communications routes, medical and signals chambers, and other subterranean military infrastructure. The company emerged from the British response to German mining activity early in the war. By January 1915, the British Expeditionary Force had recognised that German underground operations were systematic and that existing British countermeasures were inadequate. Field Marshal Sir John French and Secretary of State for War Lord Kitchener supported an investigation into the creation of dedicated mining units. Brigadier George Fowke, the Engineer-in-Chief of the BEF, worked with mining specialist John Norton-Griffiths, whose experience in civil and coal mining helped shape the organisation. The War Office formally approved the tunnelling-company scheme on 19 February 1915. The first group, numbered 170 to 177, was organised rapidly, with the 175th formed at Terdeghem in April 1915. Soon after formation, the company moved into the Railway Wood, Hooge and Armagh Wood area of the Ypres Salient. Its most prominent early operation was the construction of a large mine beneath the German position at Hooge. The company initially attempted to begin the work from a stable, but unstable sandy ground forced the tunnellers to abandon that shaft and start again from the ruins of a nearby gardener’s cottage. The completed system extended for roughly 190 feet, with a branch gallery, and was built under difficult conditions caused by a high water table and clay that expanded when exposed to air. The charge, composed of ammonal supported by gunpowder and guncotton, was detonated at 7 p.m. on 19 July 1915. The blast created a large crater and enabled British infantry to seize the far side of the position, although the area later changed hands during continued fighting. The company also contributed to the deep-mining system around Hill 60 and the Caterpillar, south-east of Ypres. Beginning in 1915, its galleries were driven beneath German positions at considerable depth and later handed over to other tunnelling companies for completion and maintenance. The company subsequently worked at Spanbroekmolen and Kruisstraat as part of the extensive mining preparations for the Battle of Messines. Together with other British, Canadian and Australian units, it helped create the underground mine network whose charges were detonated on 7 June 1917, producing the famous Messines explosions. After its work in the Messines area, the company served around Vimy Ridge, another sector characterised by extensive underground warfare. British tunnellers there inherited and expanded a complex of galleries, defensive positions and mine workings that had developed through successive French, British and German operations. The company later returned to the Ypres Salient and deployed near Loker and Kemmel, where it helped construct the Lettenberg Bunkers. These underground facilities included command and medical spaces and formed part of the defensive infrastructure of the Kemmel area. In 1918, as German forces advanced during the spring offensive, the company destroyed the entrance inclines to the Hermies catacombs. Later that year, during the British advance on the Somme, it built bridges over the Ancre. These assignments illustrate the broadening role of tunnelling companies: although their defining speciality was underground mining, they were also used for demolition, field engineering, shelter construction and mobility support. The 175th Tunnelling Company was a wartime military unit rather than a commercial brand, and no separate post-war operating identity or successor organisation is identified in the reference material.
History
The 175th Tunnelling Company formed part of the British Army’s rapid wartime development of specialist underground units. German mining beneath the Western Front had exposed weaknesses in British preparation, particularly the lack of effective counter-mining methods and underground listening equipment. Following discussions between BEF engineer leadership and mining expert John Norton-Griffiths, the War Office authorised dedicated tunnelling companies in February 1915. The earliest companies were organised within the Royal Engineers and recruited officers, sappers and experienced miners, including men whose civilian backgrounds in coal mining gave them the practical skills needed for underground work. The 175th Tunnelling Company was formed at Terdeghem in April 1915. It soon entered the Ypres Salient, initially operating around Railway Wood, Hooge and Armagh Wood under Third Army. The sector was strategically important because the surrounding heights allowed observation over the approaches to Ypres. At Hooge, the company constructed a mine beneath a German strongpoint in the grounds of the château. Difficult ground conditions caused an initial shaft to fail, but a replacement shaft was sunk through the ruins of a gardener’s cottage. The resulting gallery was approximately 190 feet long and included a branch intended to place explosive charges beneath German concrete positions. On 19 July 1915 the mine was fired, producing a crater approximately 40 metres across and helping British infantry capture part of the position. German forces later recovered the château area, and the crater landscape remained contested throughout the war. The company then took part in deep mining around Hill 60 and the Caterpillar. Its access gallery, known as the Berlin Tunnel, led towards mine chambers beneath the German positions. The company began the work in 1915 before other Royal Engineers tunnelling formations assumed responsibility for later stages. In 1916 it moved temporarily to Spanbroekmolen and worked at Kruisstraat after taking over a deep-mining project from the 3rd Canadian Tunnelling Company. Its galleries eventually reached a length of about 320 metres before the work was passed to the 171st Tunnelling Company. These projects fed into the large-scale underground preparations for the Battle of Messines. British, Canadian and Australian tunnelling companies created a network of deep mines beneath the German front. The mines were detonated on 7 June 1917, generating 19 major craters and contributing to the opening success of the offensive. The 175th was one of the Royal Engineers formations involved in the wider mining programme, although the work was distributed among several companies and cannot be attributed to it alone. After leaving the Messines area, the company moved to Vimy Ridge. Underground operations there included offensive mining, defensive galleries, underground communications and shelters. The ridge had already seen extensive French, German and British mining, and the British tunnelling companies developed a substantial gallery network as offensive mining gradually gave way to defensive underground construction. In October 1916, the 175th left the Vimy sector and returned to the Ypres Salient. At Loker, west of Kemmel and near Wijtschate, the company built underground headquarters and bunkers later known as the Lettenberg Bunkers. The surviving complex included a first-aid post and a command post, demonstrating the use of tunnelling expertise for protected operational facilities rather than mines alone. During the German advance in March 1918, the company destroyed the entrance inclines to the Hermies catacombs. In the final year of the war it also built bridges over the Ancre during the British advance on the Somme. The available references do not identify a commercial successor, post-war continuation, complete officer roster or formal disbandment date. The company is therefore best understood as a defunct wartime Royal Engineers formation whose historical significance lies in the development of British underground warfare and military engineering during 1915–1918.
- 1918
Hermies catacomb entrances demolished
[1]The company destroyed the entrance inclines to the Hermies catacombs during the German advance from Cambrai.
- 1918
Bridges built over the Ancre
[1]During the British advance on the Somme, the company undertook bridge construction over the Ancre.
- 1917
Messines mines detonated
[1]The wider British, Canadian and Australian mine system at Messines was fired on 7 June, producing 19 major craters.
- 1917
Lettenberg Bunkers constructed
[1]At Loker near Kemmel, the company constructed underground headquarters and bunkers that included command and medical facilities.
- 1916
Work at Kruisstraat and the Messines system
[1]The company took over deep-mining work at Kruisstraat and extended galleries that later formed part of the preparations for the Battle of Messines.
- 1915
War Office approves the tunnelling-company scheme
[1]The British government formally approved the creation of specialist tunnelling companies on 19 February, following concern about German underground warfare on the Western Front.
- 1915
175th Tunnelling Company formed
[1]The company was formed at Terdeghem in April and soon deployed to the Railway Wood–Hooge–Armagh Wood area of the Ypres Salient.
- 1915
Hooge mine detonated
[1]A mine constructed beneath the German position at Hooge was fired on 19 July, creating a large crater and supporting a British infantry assault.
- 1915
Deep mining begins at Hill 60
[1]The company began driving a deep gallery beneath German positions at Hill 60 and the Caterpillar before the work was continued by other tunnelling companies.
Products and positioning
A specialist First World War Royal Engineers formation focused on underground warfare and military engineering.
Marketing campaigns
- 1917Lettenberg underground headquarters
Loker and Kemmel
The company constructed protected underground facilities at Lettenberg, including command and first-aid spaces.
Outcome. The bunkers became surviving examples of Royal Engineers underground military construction in the area.
- 1916Kruisstraat and Messines mining
Ypres Salient
The company advanced galleries at Kruisstraat after taking over work from the 3rd Canadian Tunnelling Company.
Outcome. Its work contributed to the multinational mine network detonated before the Battle of Messines in June 1917.
- 1916Vimy Ridge underground operations
Vimy Ridge
The company participated in mining and defensive underground engineering in the heavily contested Vimy sector.
Outcome. British tunnellers expanded and maintained a large gallery network before the company returned to the Ypres Salient.
- 1915Hooge mining operation
Ypres Salient
The company drove a mine beneath a German strongpoint at Hooge and detonated it on 19 July 1915 in support of a British infantry attack.
Outcome. The explosion created a large crater and helped British forces seize part of the position, although German forces later regained the château area.
- 1915Hill 60 and Caterpillar deep mining
Ypres Salient
The company began deep galleries beneath Hill 60 and the Caterpillar, creating access routes and mine chambers later completed or maintained by other tunnelling units.
Outcome. The work became part of the larger underground system used in the Messines operations.
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