On what date did Britain declare war on Germany following an " unsatisfactory reply " to the British ultimatum that Belgium must be kept neutral ?
Anyhow , it is the most dangerous situation of the last 40 years . ” In order to stop a war , the Permanent Secretary of the British Foreign Office , Sir Arthur Nicolson , suggested again that a conference be held in London chaired by Britain , Germany , Italy and France to resolve the dispute between Austria and Serbia .