Intelligence services

Espionage has a long history. Although the reasons why a country would wish to spy on its neighbours have remained the same since antiquity, the ways and means of doing so have evolved considerably. Modern intelligence agencies are highly specialized state institutions with a job description that often includes more than just espionage.

The role of espionage agencies

Intelligence services are required to perform a wide range of tasks that vary greatly between nations. Nevertheless, the primary aim of all such organizations is to collect and analyse political, economic and military information using both human agents and modern technology. The information gathered in this way constitutes the basis for important decisions taken in politics, economics, military operations and scientific research.

Intelligence services also play a vital role in domestic counter-terrorism and counter-espionage. Agents working in these fields organize surveillance operations on groups that the government deems a threat and also take measures to suppress certain movements. Depending on the political circumstances involved, some intelligence agencies perform sabotage, kidnappings and even assassinations.

Intelligence agencies collect a range of both open-source and top-secret information. (symbolic image, Source: TayebMEZAHDIA via PixaBay)

Overview: the most important methods of gathering intelligence

Radar domes in Bad Aibling, Bavaria, record satellite signals. Formerly operated by the NSA, they are now the responsibility of the BND. (Source: stux via Pixabay)

HUMINT
Human intelligence – information gathered by or from human sources (spies and informants collect information)

OSINT
Open-source intelligence – information gathered from openly accessible (i.e. non-secret) sources (analysing information from the Internet, newspapers, radio, etc.)

SIGINT
Signals intelligence – information gathered from the surveillance of telecommunications (interception of radio waves, satellite transmission, cable transmissions, etc.)

IMINT
Imagery intelligence – information gathered from imaging reconnaissance (images taken by aircraft, satellites or drones using optical or sensor technology)

The history of espionage

Although espionage has a long and varied history, specialist full-time intelligence services were an invention of the 20th century. Before that, intelligence was gathered by unofficial groups established on an ad hoc basis, or by military units more widely involved in general administrative tasks or with a communications role.

The French crown moved in the 15th century to establish the “cabinet noir” to monitor postal traffic, but the first real forerunner of the modern intelligence service was the European-wide network of agents and expert cryptographers maintained by Francis Walsingham in the 16th century to serve the English Queen Elizabeth I .

Francis Walsingham headed English intelligence activities under Queen Elizabeth I.(Source: Oil painting, around 1587, via Wikimedia Commons)

An explosion at the presidential palace in Santiago de Chile: The CIA supported the military coup launched against the socialist President Salvador Allende in 1973. (Source: Biblioteca del Congreso Nacional, CC BY 3.0 CL, via Wikimedia Commons)

At the end of the 19th century, the majority of intelligence work was performed by various units of the army or navy. The British Secret Service Bureau, founded in 1909, is regarded as the first independent intelligence agency. It was from this beginning that MI5 and MI6 emerged. The 20th century saw a growth in the number and size of espionage agencies, and moves to establish their work on a professional footing intensified during the course of the two world wars.

During the Cold War, the Soviet KGB became the largest intelligence service in history, with some 480,000 employees. The East German Stasi was the largest espionage organization in relation to the size of its population, employing some 100,000 full-time employees and 189,000 informants.

The work of intelligence services has repeatedly exercised a considerable influence on the course of history. This includes a number of assassinations and operations to overthrow governments, the majority of which were organized by the CIA and the KGB during the Cold War. At the time, these two intelligence agencies were the most powerful of their kind in the world.

The most important intelligence agencies in the world

There are numerous criteria by which intelligence services can be assessed. Nevertheless, it is difficult to make definitive statements about which intelligence service was or is the best, most powerful, most dangerous and largest. This is also due to the high degree of specialization of the various intelligence services, making their work challenging to compare. The secrecy surrounding their operations also complicates assessment of their performance.

Here is an overview of the world’s most important intelligence services, both past and present:

Current secret services

Federal Office for the Protection of the Constitution (BfV)

State: Germany
Foundation: 1950
Function: domestic intelligence agency
Headquarters: Cologne
Employees (2022): c. 4,400

Federal Intelligence Service (BND)

State: Germany
Established: 1956
Function: foreign intelligence agency
Headquarters: Berlin
Employees (2024): c. 6,500

Central Intelligence Agency (CIA)

State: USA
Established: 1947
Function: foreign intelligence agency
Headquarters: Langley, Virginia
Employees (2019): c. 21,500

Federal Bureau of Investigation (FBI)

State: USA
Established: 1908
Function: domestic intelligence agency, law enforcement agency
Headquarters: Washington, D.C.
Employees (2013): c. 36,000

Federalnaja sluschba besopasnosti Rossijskoi Federazii (FSB)

State: Russia
Established: 1995
Function: domestic intelligence agency, secret police
Headquarters: Moscow
Employees (2023): c. 350,000

Government Communications Headquarters (GCHQ)

State: United Kingdom
Established: 1919
Function: signals intelligence (SIGINT) and information assurance (IA)
Headquarters: Cheltenham
Employees (2021): c. 7,180

Glawnoje Raswedywatelnoje Uprawlenije (GRU)

State: Russia
Established: 1918
Function: military intelligence
Headquarters: Moscow
Employees (2024): c. 12,000

Ministry for State Security (MSS)

State: China
Established: 1983
Function: domestic and foreign intelligence agency, security service, secret police
Headquarters: Beijing
Employees (2020): c. 110,00

Mossad

State: Israel
Established: 1949
Function: foreign intelligence agency
Headquarters: Tel Aviv
Employees (2018): c. 7,000

National Security Agency (NSA)

State: USA
Established: 1952
Function: signals intelligence (SIGINT)
Headquarters: Crypto City, Maryland
Employees (2013): c. 40,000

Secret Intelligence Service (SIS, MI6)

State: United Kingdom
Established: 1909
Function: foreign intelligence agency
Headquarters: London
Employees (2021): c. 3,644

Security Service (MI5)

State: United Kingdom
Established: 1909
Function: domestic intelligence agency
Headquarters: London
Employees (2021): c. 5,250

Former intelligence agencies

Abwehr

Abwehr
State: Germany
Established: 1928; dissolved: 1944
Function: military intelligence
Headquarters: Berlin
Employees (1939): c. 2,000

The Ministry for State Security (MfS)

State: German Democratic Republic (DDR)
Established: 1950; dissolved: 1990
Function: domestic and foreign intelligence agency, secret police
Headquarters: East Berlin
Employees (1988): c.100,000 full-time employees, c.189,000 informants

Cheka

State: Soviet Union
Established: 1917; dissolved: 1922
Function: secret police
Headquarters: Petrograd (Saint Petersburg), Moscow
Employees (1921): c. 200,000

Komitet gosudarstvennoi besopasnosti (KGB)

State: Soviet Union
Established: 1954; dissolved: 1991
Function: domestic and foreign intelligence agency, secret police
Headquarters: Moscow
Employees (1991): c. 480,000

What is an intelligence agency?

An intelligence agency is a government organization tasked with the collection and analysis of a range of political, economic and military information. They are also often deployed in a counter-terrorism and counter-espionage role and can even conduct political influence operations, sabotage and kidnappings or assassinations.

Which are the five best-known intelligence agencies?

Everyone knows the British foreign intelligence service, MI6, from the James Bond films, whilst the Soviet KGB, the American CIA and the German Stasi are best known from the Cold War. Edward Snowden’s revelations have made the American NSA world-famous.

What intelligence agencies does Germany have?

Germany maintains the Federal Office for the Protection of the Constitution (BfV) as its domestic intelligence agency; the Federal Intelligence Service (BND) as its foreign intelligence agency and the Military Counter-Intelligence Service (MAD) as its military intelligence service. Each federal state also has its own Office for the Protection of the Constitution.