[5] His fiction is principally characterised by the first person unreliable narrator, and recurring subject matter in his work includes mental illness, repressed homosexuality and adulterous relationships.

[3] Professor Emeritus of Creative Writing at Princeton, Joyce Carol Oates, makes the case that McGrath is transcribing the "nightmares of the 'shattered personality' that resonate within us all," calling his short stories "masterful and seductive, ...

[3] From The Wardrobe Mistress[11] to the current unnamed novel-in-progress on the Spanish Civil War,[12] McGrath shows increased interest in the fascistic tendencies in international politics and its effects on the psychology of characters.

In the former, for example, the main character Joan Grice uncovers the man she had been living with for a long time, who recently died, had been in the past a member of Mosley's British Union of Fascists.

Similarly, in McGrath's Last Days in Cleaver Square (2021), the narrator, an old man called Francis McNulty—a Spanish civil war veteran—is haunted by Francisco Franco's ghost, which appears in his London garden, and later in his bed, too.