[4] He was defeated at the 1906 election,[5] but in May 1907 he was selected as the Unionist candidate for a vacancy in the Stepney division of Tower Hamlets, in London, following the resignation of Sir William Evans-Gordon.
[6] At the by-election on 10 May, he won the seat[7] in a two-way contest with a Liberal-Labour candidate, Ben Cooper, Secretary of the Cigar Makers' Union.
Harris contested and won the resulting East Worcestershire by-election on 16 July,[11] just weeks before the outbreak of World War I.
He then became a commercial adviser to the trade division of the Admiralty, and in 1916 moved to the Foreign Office as Director of the Restriction of Enemy Supplies Department.
The East Worcestershire constituency was to be abolished for the 1918 general election, and Harris had been selected as the Conservative candidate for the new Moseley division of Birmingham.
She strongly denied allegations that she had ever carried him parcels or letters for him, and was supported by Austen Chamberlain, who also defended her husband against suggestions that his business had profited from his role in government.