MI5 vs MI6 is a comparison between two agencies. Both agencies have similar yet different missions and capabilities.
First, is the Security Service, also known as “Military Intelligence, Section 5”, or MI5. The UK government formally established this agency in 1909 as part of the Secret Service Bureau. In 1952, they gave it a redesign, leading it to become the agency it is today.
Second, is the Secret Intelligence Service, also known as “Military Intelligence, Section 6”, or MI6. MI6 established itself in 1909, yet has existed in various forms since the mid-16th century. (source)
This article will evaluate each service in terms of scope, accountability, and operations.
Scope: Domestic vs. Foreign
The first comparison of MI5 vs MI6 is the mission scope. For MI5, the scope is domestic. For MI6, it is foreign.
As a domestic organisation, MI5’s reputation shares overlap with other law enforcement agencies. This includes Scotland Yard, Metropolitan Police, and Interpol. In contrast to law enforcement, MI5 does not have the permission to conduct arrests. The organisation’s sole focus is civilian intelligence, and they are accountable to the public. They are not a modern secret police force. (source)
MI5’s domestic focus does not mean they object from collaboration. Collegiality is an essential element of intelligence work, especially among NATO states. A multilateral or multi-agency partnership contributes to the primary mission of MI5. That mission is “protecting the UK, its citizens and interests, at home and overseas, against threats to national security.” (source)
For matters foreign, MI6 is the best equipped. As dramatized by Albert Broccoli’s titular James Bond character, the “foreign spy” is what you will find within the service; minus the theatrics.
In essence, consider MI6 to be a copy of the United States Central Intelligence Agency (CIA). What this means is that foreign collection is the cornerstone of the MI6 mission: “to protect the UK’s people, economy and interests from overseas threats.” (source)
In contrast to MI5’s domestic limitations, the entire world is MI6’s operating ground. Because of this vast area of operations, additional layers of complexity exist within the agency.
Accountability: Home Secretary vs. Foreign Secretary
The next area of comparison between MI5 vs MI6 is accountability. UK law subjects both agencies to a detailed checks and balances system. However, both agencies answer to different entities.
Those entities are the state secretaries assigned to each agency. Ministerial responsibility for MI5 is through the Home Secretary. For MI6, it is through the Foreign and Commonwealth Development Secretary.
Outside of that, there are more similarities than differences within the area of accountability. For instance, both agencies are part of the UK national intelligence sphere. That sphere includes the Government Communications Headquarters (GCHQ), Defense Intelligence, and the Joint Terrorism Analysis Centre. (source)
Also, both agencies feed into the Joint Intelligence Committee (JIC). The JIC then uses their raw intelligence to create products that support national policy in effect. (source)
Shared Accountability
Other jointly shared accountability includes:
- Oversight from the Intelligence and Security Committee (ISC)
- Oversight from the Investigatory Powers Commissioner’s Office (IPCO)
- Oversight from the Investigatory Powers Tribunal (IPT)
- Powers and direction from the Intelligence Services Act 1994
- Protection through the Official Secrets Act
- Adherence to the Human Rights Act 1998
Unique to MI5 is the Security Service Act of 1989. The Act gives the agency a framework to work under. It details the range of threats MI5 can legally address and directives about domestic protection. Furthermore, it prevents MI5 from acting in a partisan way. As a result, the agency cannot support political parties or their goals. (source)
The central idea of the accountability side of MI5 vs MI6 is that both agencies take it seriously. Because of decades of mishaps and scandals, the intelligence sector is a prime target for the public and government. In order to combat mistrust in intelligence institutions, multiple layers of government oversight are in place. In fact, the UK has some of the strongest oversight in the world.
Operations: National Security vs. National Security
The final comparison between MI5 vs MI6 is the direction of their operations.
At the core, MI5 and MI6 exist to protect national security. As mentioned, the former does so domestically. The latter does so abroad.
One notable difference is in jurisdiction. In the event national security threats occur within the UK, MI5 is likely to be involved. However, that doesn’t mean MI6 withholds sharing their own intelligence to support MI5.
What MI5 does independently is the protection of the national infrastructure. (source) Once again, that doesn’t mean MI6 has no part in that protection. It just looks different.
Also, limitations on resources are a present factor in any organization. The way MI6 spends those resources needs to be strategic and intentional. It must support foreign operations.
Outside of that, MI6 has a more “open-ended” focus. National security is one part, but the agency handles foreign intelligence collection outside of the UK, “in support of the government’s security, defence, foreign and economic policies.” (source)
How they operate is a bit of a mystery, as most things about MI6 are. However, they are a wide expansion of MI5’s national security focus.
Why MI5 vs MI6 matters
MI5 vs MI6 is not a contentious debate by any means. What this means is that neither agency competes with the other. Furthermore, the differences between the two are minimal. They share more in common than not.
The public sphere often contains misconceptions about government agencies. This is especially true for the intelligence community. To that end, it is helpful to evaluate MI5 and MI6 in a semi-structured, in an attempt to clear up the air.
This list is not comprehensive by any means. Intelligence agencies aren’t the most transparent, for good reason. Because of this, there are obvious limitations to information is available on an open-source level.
Given these points, MI5 and MI6 are right where they need to be. Separating each agency by mission and jurisdiction helps spread resources. Also, there is directed government oversight based on each agency’s task and purpose.
