The by-election was caused by the appointment of the sitting Liberal MP, Percy Illingworth to the post of Junior Lord of the Treasury,[1] i.e. one of the government whips.
Under the Parliamentary rules applying at that time this required him to resign his seat and fight a by-election.
He had been returned unopposed in the general election of 1906 and had seen off a Liberal Unionist challenger in the general election held in January 1910 just a few weeks before by a healthy majority of 3775 votes.
[2] Shipley Liberals welcomed their member’s appointment to the government and foresaw no reason to doubt he would be re-elected in the forthcoming by-election.
[3] It was reported that the Unionists in the Shipley constituency were unprepared to fight another contest so soon after the general election [4] and the Shipley Division Liberal Unionists decided not to oppose Illingworth on the formal grounds that his appointment as a whip should not involve him in a fresh contest.