MI5 have arrested Katia Zatuliveter who is a parliamentary aide to Lib Dem MP Mike Hancock who is a member of the House of Commons Defence Select Committee. You can read about it here.
However I wonder why the Russian bother to have so many spies in the UK when so much information is so often leaked. Surely spying for the Russians in the west is being affected by the law of diminishing returns thanks to Wiki leaks and laptops on trains.
In these days of leaks is spying on the West really worth it?