The title of Sinclair's first important work, Lud Heat (1975), which juxtaposes poems with expository prose, is itself an exemplary juxtaposition. Lud was the mythological king of Britain who is supposedly buried beneath London's Ludgate, and whose name is one of the etymological contenders for the place-name of the capital. Heat is a term used throughout Sinclair's intratext to denote energy, malign or benign, often associated with certain places, and persisting through time. Early in Lud Heat, talismanic poets are imagined as ‘a sequence of heated incisions through the membranous time-layer’ (LHSB 16). Place, for Sinclair, as Rachel Potter states, ‘is understood as a continuum within history which withholds and determines the particular memories and lore to which it has borne witness’. That Lud Heat is subtitled ‘a book of the dead hamlets’ should not obscure the fact that death does not imply inertia, but potential. Lud Heat is identified as ‘The Muck Rake Book One’. The allusion operates through the epigraph to the book, from Bunyan's Pilgrim's Progress, wherein the pilgrim, ‘who could look no way but downward’, cries, ‘Oh, deliver me from this muck-rake’ (LHSB 9). At a literal level this points to the fact that Lud Heat records Sinclair's period as a grass cutter and gardener for Tower Hamlets Council in 1974, but it also alerts the reader to the existential questioning of the book that results from being both rooted in and held captive by ‘place’, its heat, and its inescapable ‘lore’.

The book's process of composition seems to have arisen out of journals, in which both dreams and reality are meticulously recorded; some of these find their way into the finished book. ‘An invasion of white rats, scuttling over the steps of a double ziggurat’ (LHSB 41), matches the precision of his daytime perceptions: ‘The white of horse-chestnut candles’ (LHSB 41). However, Sinclair is no Hopkins looking for the inscape of nature. Textual quiddity comes from chat with his mostly Irish Catholic workmates as they discuss their negative reactions to the death of Princess Anne's horse or the visit of Cardinal Heenan to the East End. The thirty-five poems of the book first appear as extensions of this journal, a poem a day.