This story sees the first on-screen appearance of Mrs. Bright, much spoken of previously in earlier episodes, but never actually seen.
Although Mrs. Bright's pet name for her husband, "Puli", may refer to a species of Hungarian sheepdog, it's more likely to be Tiger or Panther in Tamil or one of the South Indian languages.
Regarding the Bura suicide, Morse says he spoke with a Bura acquaintance, a Rhodes scholar and rugby player named Clinton. This is a reference to U.S. ex-President Bill Clinton, who won a Rhodes Scholarship to Oxford University and attended classes there in 1968 and 1969. Clinton also played rugby while at Oxford.
In discussing the 'derelict' who died from the drugs overdose, Morse says, "A soldier, possibly" and DeBryn replies, "Known Unto God." "Known unto God" is a phrase devised by Rudyard Kipling and used on the gravestones of unknown soldiers in Commonwealth War Graves Commission (CWGC) cemeteries.
De Bryn's comment about Bura screwing his courage to the sticking place is a reference to a quote from "Macbeth", by William Shakespeare. The line is from Act 1, Scene 7, when Lady Macbeth tells her husband, "But screw your courage to the sticking-place, And we'll not fail."