WT - In addition to the excellent info you give on the the defection of the Russian cypher clerk Gouzenko to Canadian authorities I am almost certain that in addition there was an unrelated Canadian sourced tip off to the UK relevant authority to the effect that a University educated traitor had been recruited and was working within the UK - passing secrets on to the Soviets. I can only recollect reading that our UK relevant authority ignored the tip off - but will try and provide further details.
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