Recruitment remained fairly steady through 1914 and early 1915, but fell dramatically during the later years, especially after the Somme campaign, which resulted in 500,000 casualties. As a result, conscription was introduced for the first time in January 1916 for single men, and extended in May–June to all men aged 18 to 41 across England, Wales and Scotland, by way of the Military Service Acts.[61][63]