Events on the battlefields in 1916 had a big impact on Britain at home.
By 1916 the Army needed more men. Hoping men would volunteer wasn't enough anymore. So in March 1916 Britain introduced conscription. But this made people angry and "conscientious objectors" refused to join up.
The poor progress on the Western Front also led the Prime Minister, Herbert Asquith, to resign. He was replaced by David Lloyd George.