Sessions made a guest appearance in a special webcast version of "Doctor Who", in a story called "Death Comes to Time", in which he played General Tannis. He occasionally appeared in the BBC series "Judge John Deed" as barrister Brian Cantwell QC. In 2007, he guest-starred in the "Doctor Who" audio adventure "100". In 2006, Sessions presented some of the BBC's coverage of The Proms and featured in one of the two "Jackanory" specials, voicing the characters and playing the storyteller in the audiobook version of Paul Stewart and Chris Riddell's children's book "Muddle Earth". In 2007 he appeared in the final episode of the second series of "Hotel Babylon", playing hotel owner Donovan Credo, and as Geoffrey Howe in 2009's "Margaret". In 2010 he played Kenny Prince in "Sherlock". Sessions appeared in the teen drama TV show "Skins" in 2011 as one of two adopted fathers of Franky Fitzgerald. He also appeared as a Brummie vicar in an episode of "Outnumbered" on BBC1. Sessions has also played two British prime ministers in films, Harold Wilson in "Made in Dagenham" and Edward Heath in "The Iron Lady". In 2013 he appeared in the premiere production of the new play "Longing". In 2014, Sessions made a short appearance in "Outlander" as Arthur Duncan. In October 2014, Sessions was heard as Gus, the mysterious, psychopathic computer that controlled the eponymous train/spaceship in the "Doctor Who" episode "Mummy on the Orient Express". Sessions also appeared as Mycroft Holmes in the 2015 film "Mr. Holmes". Sessions played the role of Arthur Lowe in the 2015 drama "We're Doomed! The Dad's Army Story". He played Dr Hermann in the 2016 film "Florence Foster Jenkins". Sessions is openly gay. A Eurosceptic, Sessions voiced his support for the UK Independence Party (UKIP) in 2014. He stated, "I get so bored with people going, 'UKIP are a bunch of racists.' They're nothing of the kind. Nigel Farage talks more sense than the rest of the politicians put together. The United States of Europe is madness." Sessions is also critical of Scottish nationalism, and has argued for the abolition of the Scottish, Welsh and European parliaments. In August 2014, he was one of 200 public figures who were signatories to a letter to "The Guardian" expressing their hope that Scotland would vote to remain part of the United Kingdom in September's referendum on that issue.