All of the novels by Arnott are engaged in the excavation of secret histories in the teasing out and restoration of events that have taken place beneath the surface of society.
The Long Firm (1999) tells of Harry Starks, a homosexual East End gangster in the 1960s. It includes references to many real life characters of the time including the Kray twins, Tom Driberg, and Judy Garland. A notable feature is that the story is told from five different points of view. It was adapted as a BBC 2 drama serial starring Derek Jacobi, Phil Daniels and Mark Strong, broadcast in July 2004 and nominated for six BAFTAs, winning two.
truecrime (2003) takes up the story of a gangster found dead at Starks's Spanish villa at the end of The Long Firm. The dead man's daughter wants to flush out Harry Starks, whom she suspects of the murder. She is an actress and uses the making of a film about old time British gangsters as a means of tempting his appearance.
Johnny Come Home (2006) shifts from a focus on the criminal underworld to the early 1970s with a plot involving The Angry Brigade and a glam rock star inspired by Gary Glitter. Johnny Come Home had been withdrawn from sale in the UK due to the presence of a villainous former bandleader named Tony Rocco; there is a real former bandleader of that name, who objected to the character's name. The book has now been reissued with the character's name changed to Timothy Royal.
The Devil's Paintbrush (2009) is set in Paris in 1903, and deals with an encounter between disgraced homosexual former British Army officer Sir Hector MacDonald and the occultist Aleister Crowley.
The House of Rumour (2012) is set in London, Southern California and Munich during the Second World War and its aftermath. An American SF writer founds a new religion, a rocket scientist dabbles in the black arts and Rudolf Hess makes his dramatic night flight to Scotland after consulting astrologists. Described by the critic Mark Lawson as 'A conspiracy thriller filled with bewildering connections, dark conjecture and arcane information, The House of Rumour perhaps most resembles The Da Vinci Code, rewritten by an author with the gifts of characterisation, wit and literacy.'
Doctor Who: A Handful of Stardust (2014) features the sixth incarnation of the Doctor from the popular TV Sci-Fi Series. It was released as part of the "Time Trips" range, which featured works by authors who have never written for the character before.
The Visa Affair: (2016) Commissioned radio play for BBC Radio 3 in October 2016> The story of how Joe Orton struggled to get a US Visa in order to visit the Broadway production of Entertaining Mr.Sloane in 1965 
The Fatal Tree: (2017) is set in 18th-century London and follows stories that relate to 'The Fatal Tree' i.e. the gallows at Tyburn. The London Guardian called it a 'Colourful descent into the underworld...absolutely gripping' According to an interview in the Scottish Sunday Herald,  'Arnott originally pitched the book as "Moll Flanders meets A Clockwork Orange"', owing to its significant use of 18th-century London street slang. The London Evening Standard described it as 'a phantasmagoric walk on the Wild side'.