It served in some of the bitterest fighting on the Western Front during World War I, leading the attack at the tank battle of Cambrai and defending Bucquoy in March 1918.

On 31 March the division was informed that it had been selected to proceed to France to join the British Expeditionary Force (BEF), and the battalion landed at Boulogne on 12 April.

[15][16][18][17][25] For the next nine months, the 49th Division took part in no major operations but was almost continuously engaged in day-to-day trench warfare, much of it in the Ypres Salient, with the considerable casualties that this entailed.

[29][30] By 14 July, the British had taken the Leipzig Redoubt on the Thiepval Spur, and while the offensive continued 49th Division remained holding this area, with a number of small actions and suffering a good deal of shelling, at the same time preparing trenches and dumps for a renewed attack.

The division was now pinned down under fire from artillery, riflemen hidden in shell craters, and from machine guns in German pillboxes on the higher ground ahead.

Two tanks would then go on up the road to help a bombing squad deal with a strongpoint known as 'Etna', while the rest turned left and advanced in line abreast to lead the infantry onto the objective.

As planned, 2/5th Bn advanced at zero to deal with the outposts, but six of its tanks failed to start (four broken down, one 'bellied' on a tree stump, and one 'ditched') The Etna strongpoint was dealt with by one platoon of 2/5th and two from 2/4th KOYLI on their right.

[15][4][17][22][35][61] During the German spring offensive, 62nd Division was brought up from reserve on 26 March and became involved in the Battle of Bapaume when it took up defensive positions around Bucquoy and Rossignol Wood to cover the exits from Puisieux.

187 Brigade led the right of the division at 08.00 on 20 July, attacking through thickly wooded country, and made slow progress, suffering heavy casualties as the men worked round stubborn German machine gun posts.

Four officers and 80 men had been captured at a strongpoint by Sergeant Laurence Calvert, MM, of 5th KOYLI, who had rushed the enemy machine gun teams single-handed, bayonetting three and shooting four.

The brigadier decided to turn the position with his reserve battalion, 5th KOYLI, which attacked at 14.30 behind a barrage, clearing defended houses and securing the road and railway.

[82][83][84] For the first few days after mobilisation, 157 and 158 Btys were billeted at the Central Schools in Danum Road, Doncaster, while Lewis and Bren light machine guns (LMGs) were set up for AA protection and the men dug air raid trenches in Elmfield Park.

The only event of note was a football match between the British and French armies in February, for which 157 LAA Bty provided AA cover with its seven available Bofors guns.

53rd (KOYLI) LAA Rgt, under the command of Lt-Col William Revell-Smith,[a] was attached to II Corps and assigned to route protection at the river and canal crossings, where all three batteries came into action.

At Helchin, E Troop (158 Bty) became the rallying point for a Guards battalion that was falling back, while the gunners brought down a Henschel Hs 126 observing for German artillery.

The landing convoys came under attack from sea and air, and 157 LAA Bty lost 15 guns and all its vehicles when its ship was sunk in Syracuse harbour.

As the campaign developed, the regiment came under the command of 73 AA Bde, which had detachments protecting airfields around Lentini, Gerbini, Agnone and Scordia, though vehicles were very short and mobility was limited.

[116][117] Even before the capture of Sicily was complete, Eighth Army reorganised for its next operation (Baytown), the landing by XIII Corps on the 'toe' of Italy beginning on the night of 2/3 September.

The campaign then bogged down and Allied forces were drawn away to the western side of Italy, leaving V Corps, supported by 2 AA Bde, to hold the eastern (Adriatic) front for many months.

[120][121][122] When fresh operations began on the Adriatic Front resumed in May 1944, 2 AA Bde moved up behind V Corps, mainly to protect landing-grounds and field gun areas.

[121][122][123][124] In October, 2 AA Bde was relieved but 53rd LAA Rgt remained in the sector as infantry under the command of 7th Motor Brigade, holding a series of ridges as the most advanced unit of Eighth Army.

53rd LAA Regiment spent three months operating a defensive smoke screen, firing mortars and Bofors in support of the forward infantry, and carrying stretchers.

[84][121][122][124][125] In March, after a short rest, the regiment returned to the front around San Clemente and Valsenio, south of Imola, as Allied forces prepared for a new Spring 1945 offensive in Italy.

When the Corps commander, Lieutenant-General Sir John Harding and other officers visited 158 Bty's forward mortar positions, they were given lunch cooked by a peacetime hotel chef, served by a professional butler, who were among the gunners.

During the division's advance through Cyrenaica a mixed column protected by a troop of the regiment came under attack by six Junkers Ju 87 Stukas escorted by Italian Fiat CR.42 fighters.

There were also failures when attackers gained successes through surprise or numbers, but by the end of the operation 57th LAA Rgt claimed a total of 103 aircraft and 10 tanks destroyed.

As part of the deception plan for the battle, the regiment simulated an attack during Operation Lightfoot by firing tracer ammunition into a smokescreen laid over the German positions.

[145] On 10 October, it was decided that 4th Indian Division would be withdrawn from the fighting in Italy to become part of 'Manna Force', ready to land in Greece as the German troops there withdrew.

Meanwhile, violent demonstrations (the Dekemvriana) had broken out 10 days earlier, and the Greek People's Liberation Army (ELAS) was in control of Piraeus when the troops arrived.

[4][79][80][149][150][153][154] In the 1920s, the battalion wore the KOYLI light infantry 'French horn' badge with silver rose centre on the shoulder straps in addition to the brass letters 'T/5/KOYLI'.