1. The government agency in the United Kingdom that is responsible for internal security and counterintelligence on British territory
   - Security Service [Brit], Military Intelligence Section 5 [Brit]

Type of: international intelligence agency

• arm-twisting
• armada
• Armadillidiidae
• Armadillidium
• armadillo
• Armageddon
• Armagnac
• armament
• armamentarium
• Armand Jean du Plessis
• Armata Corsa
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• Armed Forces Day
• Armed Islamic Group
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• armed services