[1] Delap's first work was Marcellus, a Monody, 1751, inspired by the death of Frederick, Prince of Wales, inscribed to his widow.
[1] The tragedy Hecuba by Delap was produced at Drury Lane Theatre on 11 December 1761, when the prologue, written by Robert Lloyd, was spoken by David Garrick, who also wrote the epilogue.
Delap addressed a long letter to him in 1762 in favour of a new composition, The Royal Suppliants; it was accepted, but not acted until 17 Feb. 1781, when it ran for ten nights at Drury Lane, and was published with a dedication to Henry Temple, 2nd Viscount Palmerston.
A tragedy The Captives by Delap, was staged at Drury Lane on 9 March 1786, was acted three times, and was published in the same year.
[1] Delap wrote further verse:[1] Four unacted plays in one volume of Dramatic Poems: Gunilda, Usurper, Matilda, and Abdalla, then appeared in 1803.