The individuals are Bulgarian nationals, who were alleged to be working for Russian security services, the BBC said in its report, saying they had been held as part of a major national security investigation.

London’s Metropolitan Police confirmed five people had been arrested by counter-terrorism officers in February under the Official Secrets Act and three had since been charged with possession of false identity documents with improper intention.

A police statement named them as Orlin Roussev, 45, Biser Dzambazov, 42, and Katrin Ivanova, 31.

[Only three? I kid, I kid. Keep in mind that counter-intel services often prefer to allow suspected spies to operate, in order to discover the nature and scope of their penetrations. These kinds of publicized arrests could indicate that these counter-intel got everything they needed. It could also be a retaliation for arrests in the opposing country, or to further a swap with opponents, or just to humiliate them in some way. In this particular case, though, it looks more aimed at domestic politics. Britain passed more stringent laws regarding espionage recently, and this will help validate that effort. — Ed]