MI5

What MI5 does

MI5 (legally "The Security Service") is the United Kingdom's domestic security and counter-intelligence agency, established in 1909 and headquartered at Thames House in central London. With more than 5,000 staff, it is responsible for protecting UK national security against terrorism (Islamist, extreme right-wing, Northern Ireland-related, and left-wing/anarchist), state threats (foreign espionage, sabotage, and interference), and for providing protective security advice to UK businesses and organisations through its subsidiary, the National Protective Security Authority (NPSA), launched in 2023. The agency gathers intelligence through a defined toolkit including covert human intelligence sources (CHIS), directed surveillance, interception of communications, equipment interference, and bulk personal datasets, all under warrants issued by the Secretary of State and oversight from IPCO, the Intelligence and Security Committee, and the Investigatory Powers Tribunal.

The agency's intelligence-gathering operations are supported by analytical capabilities, including AI developed in partnership with The Alan Turing Institute under a 2022 strategic agreement focused on ethical AI deployment. MI5 operates from Thames House in London, a regional headquarters in Belfast (Palace Barracks, in partnership with PSNI), and additional regional offices across the UK. In 2021 it opened the Counter Terrorism Operations Centre, a joint facility with Counter Terrorism Policing and other partners enabling minute-by-minute collaboration. The agency works closely with SIS (MI6), GCHQ, the National Crime Agency, Counter Terrorism Policing, the Home Office, Border Force, and Five Eyes intelligence partners internationally.

MI5 is a non-commercial government entity. It is funded through the Single Intelligence Account (SIA), which also funds SIS and GCHQ, with budget determined by ministers through the UK Spending Review. It does not sell products or services in any commercial sense and has no external shareholders; its only "customer" is the UK government. Recent strategic priorities have included a 35% year-on-year increase in state threat investigations, disruption of 19 late-stage attacks since 2020, and the formation of a joint bulletin regime with Five Eyes partners on threats such as Chinese espionage activity on LinkedIn.

Name

MI5

Legal name

The Security Service

Website

https://mi5.gov.uk

Company type

Private

Founded year

1909

Operating status

Operating

Headcount range

5,001–10,000 employees

Short description

MI5 is the UK's domestic intelligence agency, employing over 5,000 staff at Thames House in London to counter terrorism, state threats, and espionage, while providing protective security advice through its NPSA subsidiary.

Ownership category

akta.pro rank

Product category

Domestic Intelligence Services

NAICS

National Security (928110), National Security and International Affairs (9281)

SIC

Services-Detective, Guard & Armored Car Services (7381)

akta.pro primary industry

Intelligence (Strategic, Tactical & Technical) (BPAIAHAD)

akta.pro secondary industries

Special Operations & Counterterrorism (BPAIAHAH), Executive Protection Intelligence & Threat Management (Protective Intelligence) (BPAKABAI), Threat Intelligence Services (BPAEADAC)

Keywords

• Counter-terrorism intelligence
• Domestic security services
• State threats investigation
• Protective security advice
• Intelligence agency operations

Headquarters

HQ city

London

HQ country

United Kingdom

HQ region

Europe

Offices3 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Infrastructure, Others

Revenue model

1. Government Funding: MI5's budget is paid from the Single Intelligence Account (SIA) which also provides funding for SIS and GCHQ. The SIA's budget is decided by ministers through the Spending Review process.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels4 records

Core offering

MI5 (The Security Service) is the United Kingdom's domestic intelligence agency, established in 1909 and operating under the Security Service Act 1989. It investigates terrorism (Islamist, extreme right-wing, Northern Ireland-related, and left-wing/anarchist), counters state threats including espionage and sabotage, and provides protective security advice through its National Protective Security Authority (NPSA) subsidiary. The agency conducts intelligence gathering via lawful techniques including covert human intelligence sources, directed surveillance, communications interception, equipment interference, and bulk data analysis.

Product overview

MI5 (The Security Service) is the UK's domestic intelligence agency responsible for protecting national security against threats including terrorism, state threats, and related risks. The organization employs over 5,000 staff working from headquarters at Thames House in London and regional offices across the UK. MI5's core functions include investigating terrorist threats (encompassing Islamist terrorism, extreme right-wing terrorism, Northern Ireland-related terrorism, and left-wing/anarchist/single-issue terrorism), countering state threats from foreign governments through espionage and interference operations, and providing protective security advice through its subsidiary body, the National Protective Security Authority (NPSA). The organization gathers intelligence through various lawful methods including interception of communications, equipment interference, covert surveillance, and use of covert human intelligence sources. MI5 operates under legislative frameworks including the Security Service Act 1989, Regulation of Investigatory Powers Act 2000, and Investigatory Powers Act 2016, with oversight from the Investigatory Powers Commissioner's Office, the Intelligence and Security Committee of Parliament, and the Investigatory Powers Tribunal. MI5 does not offer commercial products or services for sale.

Differentiator

Problem solved

Functional benefit

Brands

• National Protective Security Authority (NPSA): Provides physical and personnel security advice to businesses and organisations. Launched in 2023 to replace the Centre for the Protection of National Infrastructure with an expanded remit.

Products and services

• Counter-Terrorism Investigation Services Investigative and intelligence services to detect, investigate, and disrupt terrorist threats within the United Kingdom, working in close partnership with Counter Terrorism Policing and other law enforcement agencies.
• Counter-State Threats Investigation Services Intelligence services to counter state-sponsored threats from foreign governments, including espionage, sabotage, interference operations, and illicit activity undertaken by hostile states.
• Protective Security Advisory Services (NPSA) Protective security advice on physical, personnel, and cyber resilience provided to UK businesses, organizations, and academic institutions to help mitigate national security threats.
• Intelligence Gathering Services Lawful intelligence collection services using covert human intelligence sources (agents), directed surveillance, interception of communications, equipment interference, and bulk personal datasets to support national security investigations.

Quantifiable outcome

• 19 late-stage attacks disrupted since 2020
• +2 more outcomes

Named customers3 records

Segments3 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Partnerships

Ten partnerships are on record, tiered major, core and minor.

• The Alan Turing InstitutemajorStrategic or Co-development Partner · 1 January 2022Partnership announced in 2022 for developing high-performing, ethical AI. Helps MI5 keep abreast of state-of-the-art approaches in principled AI use.
• Secret Intelligence Service (SIS/MI6)coreTechnology or IntegrationMI5 works very closely with SIS (also known as MI6), the UK's foreign intelligence agency. They have different but related functions and work together in many areas, including through joint teams.
• GCHQcoreTechnology or IntegrationMI5 works closely with GCHQ, the UK's signals intelligence agency. NPSA often works with the National Cyber Security Centre (part of GCHQ) to produce joint advice.
• Counter Terrorism PolicingcoreStrategic or Co-development PartnerMI5 works closely with Counter Terrorism Policing, a network of specialist police teams. In 2021, the Counter Terrorism Operations Centre was opened for minute-by-minute collaboration.
• Police Service of Northern Ireland (PSNI)coreStrategic or Co-development PartnerMI5 has teams based in Northern Ireland working in close partnership with PSNI at Palace Barracks, Belfast.
• National Crime Agency (NCA)majorStrategic or Co-development PartnerMI5 collaborates with the NCA on serious and organized crime that intersects with national security.
• Home OfficecoreStrategic or Co-development PartnerMI5 works particularly closely with the Home Office. A Secretary of State must give approval when MI5 seeks to use its most intrusive investigative tools.
• Five Eyes Intelligence Partners (US, Canada, Australia, New Zealand)coreStrategic or Co-development PartnerMI5 works especially closely with intelligence services in Five Eyes countries. Joint bulletins are released on threats, such as the warning about Chinese spies on LinkedIn.
• Border ForcemajorStrategic or Co-development PartnerMI5 works with Border Force on national security matters at UK borders.
• Cinquefoil TrustminorOthersA registered charity established to support current and former members of MI5 and their families who find themselves in challenging circumstances.

Scale indicators6 records

Recent moves12 records

Expansion highlights6 records

Direct peers

• Secret Intelligence Service (SIS/MI6): The UK's foreign intelligence agency, funded through the same Single Intelligence Account as MI5. Joint teams operate across counter-terrorism and counter-state work, making SIS MI5's closest operational equivalent differing only in domestic vs. foreign remit.
• GCHQ: UK signals intelligence and cyber agency co-funded through the SIA alongside MI5. Operates the National Cyber Security Centre and partners with MI5 on equipment interference, bulk data analysis, and protective security advice through NPSA.
• Australian Security Intelligence Organisation (ASIO): Australia's domestic security intelligence agency, a fellow Five Eyes partner with comparable counter-terrorism and counter-espionage responsibilities. Strong direct peer due to shared UK-derived legal framework and close intelligence collaboration with MI5.
• Canadian Security Intelligence Service (CSIS): Canada's domestic national security service, a Five Eyes partner with counter-terrorism, counter-espionage, and protective security functions directly analogous to MI5's, including advice to businesses through a parallel protective body.
• New Zealand Security Intelligence Service (NZSIS): New Zealand's domestic intelligence agency, completing the Five Eyes alongside MI5 with overlapping counter-terrorism and counter-espionage mandates and routine intelligence exchange.
• Federal Office for the Protection of the Constitution (BfV): Germany's federal domestic intelligence service, responsible for counter-extremism and counter-espionage within Germany. Comparable scope to MI5's domestic remit, with associated protection-of-constitution mandate rather than five-eyes intelligence sharing.
• Domestic Intelligence Directorate (DGSI): France's domestic counter-intelligence service under the Ministry of the Interior, covering counter-terrorism, counter-espionage, and protection of economic and scientific interests with a directly comparable mandate to MI5.

Broad incumbents

• Federal Bureau of Investigation (FBI): The United States' domestic intelligence and security service, with counter-terrorism, counter-espionage, and cyber mandates directly comparable to MI5. Closest Five Eyes counterpart for joint operations and information sharing.

Others

• National Protective Security Authority (NPSA): A wholly-owned subsidiary of MI5 created in 2023 to replace the Centre for the Protection of National Infrastructure. Provides physical and personnel security advice to UK businesses; included to highlight the closest in-house analogue rather than an independent peer.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat5 records

Key risks5 records

Key highlights7 records

Customer concentration

• Xx.com/mi5official
• Instagraminstagram.com/mi5official

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Subsidiaries1 record

Funding overview

Funding rounds

Investors

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M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about MI5