British Battalion The British Battalion ( 1936 – 1938 ) was the 16th battalion of the International Brigades during the Spanish Civil War . History . Early volunteers . A number of British volunteers , including Tom Wintringham and Nat Cohen , arrived in Spain during August – September 1936 and formed the Tom Mann Centuria - a rifle company in the German - speaking " Thälmann Column " . The Thälmann Battalion later formed part of XII International Brigade and fought in the Siege of Madrid , including the battle for University City . Another group of British volunteers - among them Jock Cunningham and John Cornford - fought with the French - speaking Commune de Paris Battalion , in the XI International Brigade . It also fought in the Siege of Madrid , including the battles for University City and Casa de Campo . In December 1936 , 145 British volunteers formed No . 1 Company of the French - speaking Marseillaise Battalion , part of the XIV International Brigade . They fought on the Córdoba front during December , and on the Madrid front during January 1937 . Heavy fighting on 15 January at Las Rozas reduced the active ranks to 67 . Formation . In January 1937 , the survivors of No . 1 Company joined with 450 new British , Irish , and Dominion volunteers at Madrigueras , near Albacete , International Brigades headquarters . They were formed into an English - speaking battalion , with three infantry companies ( Nos . 1 , 3 , 4 ) and a machine - gun company ( no . 2 ) . The battalion was numbered the 16th battalion of the International Brigades . It was formally named after Shapurji Saklatvala , the former Communist Member of Parliament ( MP ) for Battersea . However , this name never caught on and it was normally known as the " British Battalion " . ( The Spanish referred to it as " " el batallón británico " " or " " el batallón inglés " " ) . Number 1 company was called the " Major Attlee Company " after the Labour Party leader . The British Battalion was attached to XV International Brigade , " XV IB " . The other battalions were the US " Lincoln Battalion " , the crack Balkan " Dimitrov Battalion " , and the Franco - Belgian " Sixth February Battalion " . Jarama , 1937 . In February 1937 , the battalion fought at the Battle of Jarama . In a single day ' s bloody fighting on 12 February against Moors from Francisco Franco ' s Army of Africa , the British Battalion suffered 275 casualties in No . 1 , No . 3 , and No . 4 companies - leaving 125 rifleman fit for duty . On the second day of fighting , the machine gun company was surrounded by Spanish Nationalist troops and many of its members were captured . Battalion commander Tom Wintringham was injured , and Jock Cunningham took command of the battalion ' s 140 survivors . The battalion remained in the trenches at Jarama until 17 June 1937 . Brunete , 1937 . Reinforced by new recruits and strengthened by returnees from hospital , the British Battalion mustered 331 " brigaders " at the Battle of Brunete . On 6 July , " XV IB " occupied the villages of Romanillos and Boadilla del Monte , and by midnight captured the village of Villanueva de la Cañada . ( It was here that Alex McDade who wrote the song , " Valley of Jarama " , commonly heard at Brigade reunions , was killed in action . ) The following day the British were ordered to advance on Mosquito Ridge , a piece of high ground which overlooked the battalion ' s original objectives . As they left Villanueva de la Cañada they were bombed by Junkers aircraft from the Condor Legion and shelled by Nationalist artillery . The two - hour barrage and devastating heat caused heavy casualties and prevented the battalion reaching Mosquito Ridge before Franco ' s army rushed reinforcements to defend the position . Only 42 members of the battalion were left fit for service , and the battalion was withdrawn into a reserve position . Aragon , 1937 . In mid - August , the Republican 35th Division , which included " XV IB " , was moved to Aragon . The focus of the Aragon campaign was to draw - off Nationalist attacks on Santander and to capture the strategic city of Zaragoza . On 25 August the battalion took part in street fighting to capture the Nationalist strongpoint at Quinto . On 25 August the battalion attacked a strong Francoist position at Purburrel Hill , and was repelled by intense rifle and machine gun fire . The following day another assault was made on the hill , supported by the XVth Brigade antitank artillery battery , and this time the attack succeeded . Heavy fighting had reduced the battalion to 100 men , and a number of Spanish Republican troops were drafted as reinforcements for the battalion . Disbandment . On 21 September 1938 , Juan Negrín announced to the League of Nations that the Republican government would disband the International Brigades . The British battalion was withdrawn into reserve at the end of September 1938 , and on 17 October , the battalion took part in the International Brigades ' farewell parade through Barcelona . President Azaña and Prime Minister Negrín joined the crowds who took part in one of the last great Republican celebrations . On disbandment , 305 British volunteers left Spain . They arrived at Victoria Station on 7 December , to be met by a crowd of supporters including Clement Attlee , Stafford Cripps , Willie Gallacher , and Will Lawther . Notes . An estimated 300 people from Wales enlisted in the International Brigades , fighting Franco in Spain from 1936 - 39 . Of the battalion ’ s 170 Welsh volunteers , 116 were miners , one in five was married and the average age was over 30 . The South Wales miners provided the largest regional group in the British battalion . , International Brigade Memorial Trust . The International Brigade Memorial Trust has been established by veterans and historians to preserve and catalog the history of the British Battalion . Roll of Honour . The IBMT has compiled a Roll of Honour , listing the members of the British battalion who fell in Spain . The list is compiled primarily from documents held in the International Brigade Archive in the Marx Memorial Library , London and the International Brigade Archive in the Russian Centre for the Preservation and Study of Recent Historical Documents , Moscow . ISBN 10 : 0853155771 / ISBN 13 : 97808531557752012 , Paperback 320pp