Theresa May has claimed Sergei Skripal was poisoned by his former employer – Russia’s most shadowy intelligence agency with a reputation for buccaneering and aggressive operations. 

Unlike the FSB and SVR, the civilian agencies that emerged from the break-up of the KGB, the GRU, or main intelligence directorate, has never been a civilian outfit – it was always under the Soviet and then Russian defence ministry. 

It runs all of Russia’s "spetsnaz" special forces brigades, and its bat-and-globe emblem embodies an ethos for shadowy but expeditionary and "kinetic" operations rather than intelligence-gathering favoured by its rivals.  

"The GRU essentially thinks of itself as a war-fighting agency,…