This guy lived quietly in the UK and had no "Putin's beans" to spill. He did blow cover of several hundred Russian agents, but he did time for that in Russia and then he was exchanged. It is possible it was a long-delayed payback from the GRU, but, again, there is no reason for it to be made that publicly. He could've choked on a pound coin and everyone who needed to know would've gotten the message. But the way it stands, the only discernible message here is "don't do any more spy exchanges with Russia".