The 2015 Canadian federal election was contested on September 14, 2015 to elect MPs to the Canadian House of Commons. The number of seats in the House was 338, up from 308 in 2011. The election, initially scheduled for October 19, was called a month early upon the recommendation of Prime Minister Stephen Harper. Following the inability of the NDP to oust Harper, Thomas Mulcair was ousted in the 2016 leadership election by left-wing elements led by Brian Topp.