I think that the novel
The Tourist by Robert Dickinson (Orbit, 2016) deserves a place here This is on account of it having a strong focus on technological espionage and a serpentine plot. The novel is very much on the Science fiction end of the Spy-Fi spectrum, but definitely constitutes Spy Fi for all that.
https://www.goodreads.com/book/show/29467314-the-tourist
Dickinson seems to be a not-so-young denizen of Brighton who has had two (I think) self-published novels out before, this being his first big exposure publication.
In this, a 24 century civilisation - stratified and militarised, having survived an unspecified g;obal catastrophe - is revisting the 21st Century for reasons of tourism. They do so with the knowledge and consent of the 21st Century `natives` and have domes built outside our cities in which the `translsation` (Time travel) devices are housed.
The narrator works for as a tourist rep chaperoning these future time ttourists. (Hence, we get the 24th century take on our own times, which is often quite perspicacious). He becomes involved in a case where one of his own clients goes missing on a tour to a shopping mall. The subsequent investigation opens a can of worms in which we discover that the absent tourist could be a drug seller, a terrosist or - more likely - something much worse....
The tale combines the twisty wierdness of A.E. Van Vogt. the sociopolitical satire of the Strugatsky brothers and the slightly creepy Englishness of Christopher Priest. We get a lot of dark humour and intrigue in a novel which works through offering a series of revelations in dribs and drabs.
Online, a lot of reviewers have had gripes about how the book ends - or ather doesn't end! I must say that, whilst I wasn't all that put off by the complex plotline
per se (I've got through John Le Carre novles which were just as Byzantine and still got something out of them) I do agree that the author fails to tie up the loose ends and concludes with a kind of lazy delirium.
It was this that prevented the novel from being a Contemporary British Mini-Classic of Science Fiction that it could otherwise have been. Still, it was the best Science fiction novel I have read in about ten years - and reminded me ( and God knows I needed to be) of why I liked the genre to begin with. Robert Dickinson is a talent to keep an eye on.