 On 4 August 1914 , Lady Diana 's future husband , Duff Cooper , then a Foreign Office official , dined at the Ritz with the Earl of Essex and his American wife , Adele Capell ( née Grant ) and Patrick Shaw @-@ Stewart , and later that day announced that World War I had broken out to the party . Before the war began , the German and Austrian embassies both retained tables at the Ritz Restaurant . The hotel suffered during the war , and lost nearly £ 50 @,@ 000 in 1915 alone ; the ballroom was usually empty and lights went out by 10pm , but rooms were still in demand and the hoteliers believed it to be worth keeping open . <unk> such as Lady Cynthia Asquith , daughter @-@ in @-@ law of H. H. Asquith and Lord Basil Blackwood were documented in her diaries to have dined at the Ritz in the spring of 1916 . The following year , she held a lavish dinner party with the likes of Osbert Sitwell , Gilbert Russell and Maud <unk> and Clare Tennant . 
