In the early 1980s. he was involved in politics as a member of the
Alliance Party of Northern Ireland, but ceased to be active as his legal career took off. In 1989, at the age of 25, Larkin was appointed as
Reid Professor of Criminal Law, Criminology and Penology at
Trinity College Dublin. He returned to Northern Ireland in the 1990s to work at the Northern Ireland Bar, specialising in administrative law, civil liberties and human rights, competition and constitutional law, defamation and judicial review. On 20 November 2013, he recommended eliminating prosecutions, inquests or inquiries into events which preceded the
Good Friday Agreement of 1998. Certain politicians and policemen accused him of attempting to violate
international law. On 25 November, he received a letter from
Jim Allister regarding
Traditional Unionist Voice allegations against the
BBC to which he replied three days later saying that it would not be appropriate for him to comment on that issue. On 10 June 2014, he attended hearing on the so-called
on-the-run letters. ==Views==