Spy games: expulsion of diplomats shines light on Russian espionage

The war in Ukraine has prompted an exodus of Russian diplomats'. Does it mark the end of an era?

Russia-Ukraine war: latest updates

The unprecedented wave of expulsions of Russian diplomats from European capitals - now close to 400 - is not just a symbolic, if reversible, act of revulsion at the war crimes for which Russia stands accused. It is part of a decades long battle to police the dividing line between espionage and diplomacy, one in which the west of late has been accused of too often ignoring a resurgence in Russia's clandestine activities, either because of an excessive focus on domestic terrorism, or excessive reliance on intercepts.

Sir John Sawers, the former head of M16, last year said he suspected the west was picking up only 10% of Russia's espionage.