Michael Moorcock, The Chinese Agent (1970; Mayflower, 1979)
I must've read this one about 30 years ago, probably in a library copy, because I didn't own a copy until I found one in a 2nd-hand shop a few months back. An enjoyable two or three hours, given that MM probably devoted all of a couple weeks to writing it. There are some passages of pretty evocative description – devoted mostly to the more sordid districts of London, to the old Notting Hill and Portobello Road – and gratifying few of the terrifically sloppy passages one finds in so much of his work of the 60s and 70s.
This is non-fantasy, non-SF Moorcock – a clear precursor of the "serious" city books of later years, Mother London (1988) and King of the City (2000). Gosh he loves London, and that affection suffuses the passages of urban description. Plotwise it's nominally a spy thriller – well, actually a spy farce, the sort of thing that got filmed so delightfully in all those Peter Sellers movies of the day. The protagonist is Jerry Cornell, who is a kind of down-at-the-heels, bourgeois version of Jerry Cornelius; he's working, improbably, for the British secret service. The novel has him revisiting the bosom of his disgusting Cockney family (rather more outrageously gross than the other Jerry C's), falling into bed with a shy receptionist and a Mata Hari-like femme fatale, and blundering his way thru a highly improbable comedy of mistaken identities, stolen secret documents, and time-bombs.
A bit of literary popcorn, in the final analysis – but it never aspires to be anything higher than light entertainment, and that's sometimes refreshing from a writer who can get all too "heavy" when he furrows his brow and becomes serious.