HomeUPSCThe event that triggered the British declaration of war on Germany on August 4, 1914, was: 216. The event that triggered the British declaration of war on Germany on August 4, 1914, was:By Admin / October 4, 2025 A. Russian mobilization. B. the German invasion of Belgium. C. the German declaration of war on Russia. D. the German declaration of war on France. ✅ The correct answer is option B.