[2] The 2nd Army during World War I, fought on the Western Front and took part in the Schlieffen Plan offensive against France and Belgium in August 1914.

The 2nd Army laid siege to, and took the Belgian fortresses around Namur, and fought General Charles Lanrezac's French 5th Army at the Battle of Charleroi on 23–24 August 1914 and again at St. Quentin on 29–30 August 1914.

2nd Army bore the brunt of the Allied attack in the Battle of the Somme.

It had grown to such an extent that a decision was made to split it into two still-powerful armies.

[3] A large proportion of the Army would be wiped out during the joint Anglo-French offensive on the Somme.