The Intelligence Bureau (IB) is a premier internal security and counterintelligence institution of the Republic of India, operating under the administrative control of the Ministry of Home Affairs (MHA). Its origin traces back to the British colonial era, established as the Central Special Branch on December 23, 1887, to gather intelligence on political unrest, particularly following the formation of the Indian National Congress in 1885. It was formally renamed the Intelligence Bureau in 1920, reflecting the directive in Section 40(2) of the Government of India Act 1919 to keep the government informed on matters of security.
The IB functions primarily on executive authority and, unlike many other government bodies, does not have a dedicated parent statute, a fact that remains a recurring subject of debate. Its existence is recognized in the Constitution under Schedule VII, Union List, Entry 8, which mentions the "Central Bureau of Intelligence". The IB's mechanism involves gathering, collating, and disseminating actionable intelligence on internal threats like terrorism, espionage, and insurgency, but it is officially a civilian organization without police powers or a prosecutorial mandate. However, a 1987 notification conferred powers of Superintendent of Police on IB officers of the rank of Assistant Directors.
The IB is closely connected to the Research and Analysis Wing (R&AW), which was created in 1968 to handle external intelligence after the IB's responsibilities were bifurcated following the 1962 Indo-China War. Another related institution is the National Investigation Agency (NIA), established by the National Investigation Agency Act, 2008, to address the gap in investigation and prosecution, as the IB is solely an intelligence collection agency. A recent change, announced in August 2026, is a major expansion drive to double the agency's strength, with a focus on strengthening deployment at immigration checkpoints under the Bureau of Immigration (BoI), which is part of the IB.