Judas 62 : a novel / Charles Cumming.

Enhanced descriptions from Syndetics:

After a lifetime working with BOX 88, the transatlantic counterintelligence agency so covert that not even the CIA knows of its existence, master spy Lachlan Kite has made plenty of enemies. And now, as the director of the outfit's operations in the UK, one of those past enemies has him in their sights...

1993: Student Lachlan Kite is sent to post-Soviet Russia, a spy in the guise of a language teacher. Embedded in the town of Voronezh, Kite's mission is to extract a chemical weapons scientist before the man's groundbreaking research falls into the wrong hands and shuttle him across the border to freedom in Ukraine. But Kite's mission soon goes wrong and he is left stranded in a hostile city with a former KGB officer on his trail.

2020: Thirty years after that dangerous mission, Kite discovers that its outcome put his name on the notorious "JUDAS" list--a record of enemies of Russia who have been targeted for assassination. Kite's fight for survival takes him to Dubai, a city crawling with international intelligence officers, where he enters into a deadly game of cat-and-mouse with the Russian secret state.

The newest installment in the saga of "a spy for the 21st century" (Daily Mail) combines two pulse-pounding narratives that show why Cumming is among the top tier of espionage authors examining the reality of spycraft in the post-Cold War era.