Other themes that are touched on, that feature in other works, are; ridicule of authority, the hospital administration perform a dance number; mockery of racism, Marlow's banter with Ali; and notions of childhood innocence, the scenes with young Philip reminiscent of Blue Remembered Hills(1979). Notably absent from The Singing Detective are child abuse (Moonlight on the Highway, Hide and Seek), voyeurism (Blackeyes), politics and hypocrisy (Vote, Vote, Vote for Nigel Barton), England's decaying culture (The Bonegrinder, Moonlight on the Highway) and the 'visitation' plot structure (Brimstone and Treacle, Pennies From Heaven and countless others).

Further consistencies with his other work are the use of humour and music. Even his grimmest stories such as Joe's Ark(1974) have been injected with a liberal dose of humour. In The Singing Detective, the hospital scenes are almost farcical; the comic stereo-types of petty criminal Reg and his tormentor, the incontinent Mr. Hall. The pseudo-musical format placed the play as the middle part of a trilogy, preceded by Pennies from Heaven(1978) and succeeded by Lipstick on Your Collar(1993), which heavily featured the music of the 30's, 40's and 50's respectively. The songs in Detective provoke Marlow's memories, they were, Potter says "hard little stones thrown at Marlow". Subsequently Lipstick on Your Collar was accused of being too formulaic in using the pseudo-musical format a little less convincingly than in Pennies and Detective. Reusing the format could have been provoked by the huge success of The Singing Detective and Potter's desire to recreate that success, which he never managed before his death. Potter himself says in Waiting for the Boat, "I'm not a member of the Social Democratic Party, but I do believe in recycling old material".