Trainspotting's vocabulary, for most of the novel, hints at an engagement with revolutionary politics to come: 'Bad Blood', to those familiar enough with the tradition to recognise the allusion, offers instead denigration and reversal. Welsh's allusion is too subtle to be noticed by those not familiar with Trotsky's writing or Trotskyist politics but is, in the context of all the knowing asides and 'little words', impossible to miss by those who know the political context. Welsh does not extend an analysis of revolutionary socialism comparable to his attacks on reformist Labourism. The political function that 'Bad Blood's' narrative uncertainty fulfils, instead, is to shock and upset, to denigrate and to deny. His emotive material — suggested child torture — and his use of allusion, substitute emotional evocation for political analysis. Mitchell's narrative serves a purpose, but it is a purpose quite separate from the rest of the novel. He is written in to the story in order to allow a suitably dramatic and grisly mocking of the revolutionary tradition. It is in this sense, then, that one can describe 'Bad Blood' as being in bad faith: its narrative devices, and its subject material, exist to manipulate a political shock effect that the rest of Trainspotting cannot produce. Welsh displaces a political dilemma into a moment for allusive denigration. It is a moment of Trainspotting as an example of literary anti-Trotskyism.
From 'Is Life Beautiful? Narrative Uncertainty and 'Literary anti-Trotskyism' in Trainspotting' by Dougal McNeill in the International Journal of Scottish Literature - which includes among other things a discussion of an old classic International Socialism article by Audrey Farrell, Addicted to Profit - Capitalism and Drugs from 1997.
Hat tip - the ISJ pick of the quarter