Ivor knew of his elder brother's spy work, but it seems doubtful his brother knew of his. Counter-espionage agents at MI5, however, even Ewen's boss John C. Masterman, seem to have suspected Ivor in general because of his outspoken Communist politics, his hanging around with scruffy Russians and housing a Jewish refugee in his house in the country. By far the greatest suspicions were aroused by Ivor's passionate support of international ping-pong, which seemed so eccentric to MI5 that they assumed it had to be a cover for something else. They even tapped his phone and opened his mail, creating three volumes on him by early 1942, but found nothing specific, much to Ewen's relief, since he was always worried that his own career in MI6 would be adversely affected by the activities of his left-wing brother.