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

• American mistletoe
• American mountain ash
• American oil palm
• American olive
• American organ
• American oriole
• American parasol
• American parsley fern
• American Party
• American pasqueflower
• American pennyroyal
• American persimmon
• American pit bull terrier
• American plaice
• American plan
• American plane
• American pulsatilla
• American quaking aspen
• American raspberry
• American rattlebox
• American red elder
• American red plum
• American red squirrel
• American redstart
• American Revised Version