UK security services

In the United Kingdom, the umbrella term security services refers to the UK government agencies collectively responsible for espionage, counterespionage, counterterrorism and other covert activities.

This typically means:
 * Security Service, more commonly known as MI5
 * Secret Intelligence Service (SIS), more commonly known as MI6

Some people also count Special Branch and the Metropolitan Police Anti-Terrorist Branch as part of the security services.