C'mon, you surely must know that the KGB outlet he graduated from was a math school on steroids, not the 007 training facility. The chances of him still being an agent because of that are well comparable to being simply hard-pressed into cooperation after his company acquired a momentum.
Most of the famous "Cambridge Five" studied languages and history and were some of the most successful Russian spies of the 1950's. Just because he studied math does not excuse him from his association with the KGB.
I'm not saying he's still active, but those relationships are for life, and you don't just walk away from the KGB/FSB unscathed. Just ask Alexander Litvinenko.
