The 1911 West Ham North by-election was a Parliamentary by-election which was held on 8 July 1911. It returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom, elected by the first past the post voting system.
Vacancy.
The Under-Secretary of State for the Home Department, Charles Masterman had been the Liberal MP here since gaining the seat from the Conservatives in 1906. However, his December 1910 re-election was later declared void after his defeated Conservative opponent had petitioned the courts. This meant a repeat election was required. Masterman's agent had been found guilty of corrupt practices. The Counsel for Masterman admitted that the expenses had exceeded the legal limit, and that the agent, who was in bad health, had failed to check the accounts. The counsel for the petitioner (the defeated Conservative candidate), while contending that it was impossible to avoid bringing the petition, in view of the illegal proceeding which had been shown, publicly stated that no imputation had been made against Masterman's integrity, honour, or conduct. In giving judgment the Judges fully concurred with these observations, but declared that it was impossible to give relief and excuse the irregularities disclosed.
Electoral history.
In the eight electoral contests since the seat was created in 1885 the Liberal had won five times and the Conservatives three. In each case, the seat had gone to the party who subsequently formed the government. Masterman had comfortably retained his seat at the last general election;
! scope="col" colspan="2" style="width: 130px"|Party
! scope="col" style="width: 17em"|Candidate
! scope="col" style="width: 5em"|Votes
! scope="col" style="width: 3.5em"|%
! scope="col" style="width: 3.5em"| ;templatestyles src="Template:Tooltip/styles.css" / ;±%
! colspan="3" style="text-align: right; margin-right: 0.5em" | Majority
! colspan="3" style="text-align: right; margin-right: 0.5em" scope=row | Turnout
! style="text-align:right;" | Swing
Campaign.
The prominent national issue of the day was the Liberal government's Veto Bill, that they had introduced to curb the power of the House of Lords.
The Liberal candidate de Forest, in his election address stated that he was in favour of land nationalisation, Irish Home Rule, revised licensing laws, female suffrage and equality of religion in education.
Result.
Polling took place on Saturday 8 July. The Liberals held the seat on a reduced poll with a slight increase in their vote-share:
! scope="col" colspan="2" style="width: 130px"|Party
! scope="col" style="width: 17em"|Candidate
! scope="col" style="width: 5em"|Votes
! scope="col" style="width: 3.5em"|%
! scope="col" style="width: 3.5em"| ;templatestyles src="Template:Tooltip/styles.css" / ;±%
! colspan="3" style="text-align: right; margin-right: 0.5em" | Majority
! colspan="3" style="text-align: right; margin-right: 0.5em" scope=row | Turnout
! style="text-align:right;" | Swing
Baron de Forest described his victory as "the last nail in the coffin of the House of Lords," attributing his victory to the government's Veto Bill and the advanced radical platform on which he stood. Wild blamed his defeat on his potential helpers preferring to watch the Eton v Harrow school cricket match.
Aftermath.
A General Election was due to take place by the end of 1915. By the autumn of 1914, the following candidates had been adopted to contest that election. 
Due to the outbreak of war, the election never took place. At the outbreak of war, Unionists tried to paint de forest as an enemy sympathiser, despite the fact that he joined the Royal Navy Volunteer Reserve. Under boundary revision, the constituency was abolished and replaced mainly by Upton for the 1918 elections. De Forest did not stand as a candidate at the 1918 elections. Wild did stand and was the endorsed candidate of the Coalition Government, helping him win the new seat;
! scope="col" colspan="2" style="width: 130px"|Party
! scope="col" style="width: 17em"|Candidate
! scope="col" style="width: 5em"|Votes
! scope="col" style="width: 3.5em"|%
! scope="col" style="width: 3.5em"| ;templatestyles src="Template:Tooltip/styles.css" / ;±%
! colspan="3" style="text-align: right; margin-right: 0.5em" | Majority
! colspan="3" style="text-align: right; margin-right: 0.5em" scope=row | Turnout
References.
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