sentences:  He played David Cameron in "The Three Lions", a comedy written by William Gaminara, a role for which he was nominated as best actor by "The Stage" at the Edinburgh Festival of 2013.Lockhart returned to the role when the play was later staged at the St James Theatre, London, in 2015, and stayed with the production when it moved on to the Liverpool Playhouse.He is the author of a handbook for actors called "Heavy Pencil", and of a thriller, "The Lizard", published in 2020.