The QF 4.5 served throughout the Great War, principally with the Royal Field Artillery, beginning with 182 guns in 1914, with 3,177 more produced during the war.

At the beginning of the First World War a brigade of three six-gun howitzer batteries was part of each British infantry division.
In February 1917, divisional artilleries were consolidated into two field brigades each with three batteries (A, B, C) of 18-pounder guns and one battery (D) of 4.5-inch howitzers.
The balance were formed into army field brigades with the same organisation.

Following experience gained in the Battle of the Somme in the summer of 1916, its role on the Western Front was defined in January 1917 as "neutralising guns with gas shell, for bombarding weaker defences, enfilading communications trenches, for barrage work, especially at night, and for wire cutting in such places which the field guns could not reach".

During advances such as at Messines in June 1917, the gun was typically employed in "standing barrages" of HE on the enemy forward positions ahead of the 18-pounders' creeping barrage, and gas shelling following bombardments.

There were 984 guns in service on the Western Front at the armistice and 25,326,276 rounds had been fired.

The 4.5-inch howitzers were also used by British batteries in the campaigns in Gallipoli, the Balkans, Palestine, Italy and Mesopotamia.
The QF 4.5 served throughout the Great War, principally with the Royal Field Artillery, beginning with 182 guns in 1914, with 3,177 more produced during the war.
At the beginning of the First World War a brigade of three six-gun howitzer batteries was part of each British infantry division. In February 1917, divisional artilleries were consolidated into two field brigades each with three batteries (A, B, C) of 18-pounder guns and one battery (D) of 4.5-inch howitzers. The balance were formed into army field brigades with the same organisation.
Following experience gained in the Battle of the Somme in the summer of 1916, its role on the Western Front was defined in January 1917 as "neutralising guns with gas shell, for bombarding weaker defences, enfilading communications trenches, for barrage work, especially at night, and for wire cutting in such places which the field guns could not reach".
During advances such as at Messines in June 1917, the gun was typically employed in "standing barrages" of HE on the enemy forward positions ahead of the 18-pounders' creeping barrage, and gas shelling following bombardments.
There were 984 guns in service on the Western Front at the armistice and 25,326,276 rounds had been fired.
The 4.5-inch howitzers were also used by British batteries in the campaigns in Gallipoli, the Balkans, Palestine, Italy and Mesopotamia.
QF 4.5-inch howitzer