Irish actor Allen Leech is best familiar to the audience for portraying the British spy John Cairncross in the historical drama The Imitation Game (2014) and Tom Branson in the historical drama series Downton Abbey (2010-15). His performances in both these ventures earned Leech nominations at the Irish Film and Television Awards in the Supporting Actor category.

Since his film debut in the 2003 Irish movie Cowboys & Angels, Leech has appeared in over a dozen features and a number of tv shows, notable among which are the fantasy drama From Time to Time (2009), the action drama The Sweeney (2012), the historical drama tv series The Tudors (2007-10) and the crime drama series Bellevue (2017). In 2018, Leech played a pivotal supporting role in the biographical drama Bohemian Rhapsody, which revolved around the renowned British rock band Queen. His 2019 release includes Downton Abbey. Directed by Michael Engler, starring Michelle Dockery and Laura Carmichael in prominent roles.