Big Brother 2014, also known as Big Brother 15 and Big Brother: Power Trip, was the fifteenth series of the British reality television series Big Brother, hosted by Emma Willis and narrated by Marcus Bentley. It began on 5 June 2014 on Channel 5 and lasted for 72 days ending on 15 August 2014, making it the longest series to air on Channel 5. It was the fourth regular series and the tenth series of Big Brother overall to air on the channel. The series was officially confirmed on 3 April 2012 when Channel 5 renewed the show until 2014. It was therefore the final regular series to be included under the then contract.
The series was controversially won by Helen Wood, who won the £100,000 prize fund beating bookies' favourite Ashleigh Coyle by a margin of 4,631 votes. Wood became the first woman to win the competition since the show's inception on Channel 5. It was then revealed that just 1.2% of the vote, separated Helen and Ashleigh, making it one of the closest results in Big Brother history. This was the first series of Big Brother UK where both the runner-up and the winner were women.
Wood would later return the following year in Big Brother 16 as part of a secret twist that saw her and two other "legendary" former Housemates, Brian Belo and Nikki Grahame, re-enter the House as part of "Time Warp" week. In addition, Mark Byron and Matthew Davies also made an appearance in a shopping task.
Auditions for the series opened on 19 August 2013, the same day as the final of Big Brother 14. Like the previous series, there were no open auditions. Housemates were chosen from online applications. In order to become a housemate, applicants were required to record a 90-second video and complete an online application form.
Emma Willis returned as the main presenter of the show. She also continued to present Big Brother's Bit on the Side, along with Celebrity Big Brother 11 winner Rylan Clark and Iain Lee. Celebrity Big Brother 13 housemate Luisa Zissman acted as a regular panellist on the show.Matt Johnson guest hosted an episode of Bit on the Psych in July.