Byline: James Owen

Espionage The Illegals Russia's Most Audacious Spies and the Plot to Infiltrate the West by Shaun Walker Profile PS22 pp448

In the aftermath of Russia's assault on Ukraine in 2022, aides to the mayor of the town of Vasylkiv confided to western journalists that the threat there had also come from within. A fifth column of sleeper agents had moved in months before, throwing of false identities to join the attack.

This proved to be rumour, but as Shaun Walker, one of those journalists, knew well, Russia has long infiltrated such spies into target nations. Trained for years in the culture of another country, they are known as "illegals", to distinguish them from the "legal" intelligence officers who work out of embassies.

Perhaps the best-known examples now are fictional ? Marvel films' Natasha Romanof f (Black Widow) and characters in the TV series The Americans ? but in 2010 the US exposed a ring that included the glamorous Anna Chapman as well as a supposedly Canadian

AP couple, Donald Heathfield and Tracey Foley. So dedicated had the pair been to their 25-year mission that, growing up in Massachusetts, their sons had no idea their parents were Russian until the FBI kicked in the door. As Walker shows in this gripping history of such operations,...