MI5, officially called the Security Service, is a British counter-intelligence and security agency. Its remit covers the protection of British Parliamentary democracy and economic interests, and fighting serious crime, terrorism and espionage within the United Kingdom. It is mainly concerned with internal security, whilst the Secret Intelligence Service (MI6) looks after external security. Within the government community, MI5 is colloquially known as Box (after its official wartime address of PO Box 500 and its current address—PO Box 3255, London SW1P 1AE) or simply Five. The organisation is based since 1995 at Thames House, Millbank, London. Previous headquarters have been 140, (aka "Russian House") Gower Street, 1976-95; Leconfield House, Curzon Street, 1945-76; and 124-26, Cromwell Road, 193?-37. The sites at Gower and Curzon streets are now demolished.
As well as the current MI5 and MI6, there have been a number of British military intelligence groups designated as MI-(section number) existing at various times since the First World War, which have now been abandoned or subsumed by MI5, MI6 or GCHQ. These included MI1 (Directorate of Military Intelligence), MI2 (intelligence in the Soviet Union and Scandinavia), MI3 (Germany and Eastern Europe), MI4 (aerial reconnaissance during the Second World War), MI8 (interception and interpretation of communications), MI9 (covert operations and PoW escape), MI10 (weapons and technical analysis), MI11 (Field Security Police), MI12 (German specialists), MI14 (German specialists), MI17 (secretariat for MI departments) and MI18 (Prisoner of War debriefing). MI(R) was responsible for the creation of the secret Home Guard Auxiliary Units. Most British military intelligence is now gathered and analysed by the Defence Intelligence Staff, part of the Ministry of Defence, with support from MI6, GCHQ and allied intelligence organisations.
Like the SIS, the Security Service has its basis in the Secret Service Bureau, founded in 1909 as an organisation to control secret intelligence operations. The Bureau was originally split into a naval and army section. The naval section came to specialise in espionage activities in foreign countries, while the army section increasingly undertook counter-espionage activities within the UK. This new split was formalised. After a series of bureaucratic designation changes in which it was known as MO5 (Directorate of Military Operations Section 5) and gained various subdepartments denoted by letters of the alphabet, the domestic section came to be known as MI5 (Directorate of Military Intelligence Section 5), a name it retains today (albeit informally).
Its founding head was Vernon Kell, who remained head until the early part of the Second World War. Its role was originally quite restricted; it existed purely to ensure national security through counter-espionage. It originally worked in concert with the Special Branch of the Metropolitan Police; the Security Service was responsible for overall direction and the actual identification of foreign spies, while the Special Branch provided the manpower for the investigation of their affairs and their arrest and interrogation.
The Security Service was very successful (against admittedly weak opposition) in the pre-war years. It was founded in a climate of hysteria over a supposedly huge network of German spies—numbers in the hundreds of thousands were quoted—who were apparently ready to perform espionage and sabotage activities in advance of a German invasion. In reality, no invasion was planned, and Germany had a mere handful of incompetent amateur spies active in Britain—just over 20. MI5 was quickly successful in identifying this group, and Kell took the intelligent decision not to arrest them but to keep them under surreptitious observation until the outbreak of war. He reasoned that if they were arrested Germany would simply send more in their place, who would be unknown to the authorities. Instead he waited until the eve of war—he was given twelve hours' notice of its outbreak—to arrest the entire network, thus depriving Germany completely of reliable intelligence from within Britain.
After this auspicious start, the history of MI5 becomes darker. It was consistently successful throughout the rest of the 1910s and the 1920s in its core counter-espionage role. Germany continued to attempt to infiltrate Britain throughout the war, but using a method that depended on strict control of entry and exit to the country and, crucially, large-scale inspection of mail, MI5 was easily able to identify all the agents that were dispatched. In post-war years attention turned to attempts by the Soviet Union and the Comintern to surreptitiously support revolutionary activities within Britain, and MI5's expertise combined with the early incompetence of the Soviets meant the bureau was successful once more in correctly identifying and closely monitoring these activities.
However, in the meantime MI5's role had been substantially enlarged. Due to the spy hysteria, MI5 was formed with far more resources than it actually needed to track down German spies. As is common within governmental bureaucracies, this meant it expanded its role in order to use its spare resources. MI5 acquired many additional responsibilities during the war. Most significantly, its strict counter-espionage role was considerably blurred. It became a much more political role, involving the surveillance not merely of foreign agents but of pacifist and anti-conscription organisations, and organised labour. This was justified on the basis of the common (but mistaken) belief that foreign influence was at the root of these organisations. Thus by the end of the war MI5 was a fully-fledged secret police (although it never had the powers of arrest), in addition to being a counter-espionage agency.
This expansion of its role has continued, after a brief post-war power struggle with the head of the Special Branch, Sir Basil Thompson. MI5 also managed to acquire responsibility for security operations not only on Great Britain but throughout the Empire, and with the decline in the Empire the Security Officers based in the British High Commissions returned to London and joined the Service, which gave it a significant role in Ireland. MI5 now has a role similar to that of the American FBI, if not as extensive, which includes crime-prevention activities as well as political surveillance and counter-espionage. This expansion had happened almost entirely without supervision; MI5 had no responsibility to Parliament, and was often able to act with considerable independence even from the Cabinet and Prime Minister. Since 1994, MI5 activities have been subject to scrutiny by Parliament's Intelligence and Security Committee.
MI5's pre-war Irish operations were an unmitigated disaster. Its operation was penetrated by the IRA, and even before Michael Collins ordered a ruthless purge of MI5's Irish agents—almost all of whom were assassinated—it was unable to provide useful intelligence on the Irish republican movement during the Home Rule and independence controversies.
MI5's decline in counter-espionage efficiency began in the 1930s. It was to some extent a victim of its own success; it was unable to break the ways of thinking it had evolved in the 1910s and 1920s. In particular, it was entirely unable to adjust to the new methods of the NKVD, the Russian secret intelligence organisation (later KGB). It continued to think in terms of agents who would attempt to gather information simply through observation or bribery, or to agitate within labour organisations or the armed services, while posing as ordinary citizens.
The NKVD, however, had evolved more sophisticated methods; it began to recruit agents from within the Establishment, most notably from Cambridge University, who were seen as a long-term investment. They succeeded in gaining positions within the Government (and, in Kim Philby's case, within British intelligence itself), from where they were much more easily able to provide the NKVD with sensitive information. The most successful of these agents—Harold 'Kim' Philby, Donald Maclean, Guy Burgess, Anthony Blunt and John Cairncross—went undetected until after the Second World War, and were known as the Cambridge Five.
Second World War
MI5 experienced further failure during the Second World War. It was chronically unprepared, both organisationally and in terms of resources, for the outbreak of war, and utterly unequal to the task which it was assigned—the large-scale internment of enemy aliens in an attempt to uncover enemy agents. The operation was badly mishandled and contributed to the near-collapse of the agency by 1940.
One of the earliest actions of Winston Churchill on coming to power in early 1940 was to sack the agency's long-term head, Vernon Kell. He was replaced initially by the ineffective Brigadier A.W.A. Harker, as Acting Director General. Harker in turn was quickly replaced by David Petrie, an SIS man, with Harker as his deputy. With the ending of the Battle of Britain and the abandonment of invasion plans (correctly reported by both SIS and the Bletchley Park ULTRA project), the spy scare eased, and the internment policy was gradually reversed. This eased pressure on MI5, and allowed it to concentrate on its major wartime success, the so-called "double-cross" system.
This was a system based on an internal memo drafted by an MI5 officer in 1936, which criticised the long-standing policy of arresting and sending to trial all enemy agents discovered by MI5. Several had offered to defect to Britain when captured; before 1939, such requests were invariably turned down. The memo advocated attempting to "turn" captured agents wherever possible, and use them to mislead enemy intelligence agencies. This suggestion was turned into a massive and well-tuned system of deception during the Second World War.
Beginning with the capture of an agent called Owens, codenamed SNOW, MI5 began to offer enemy agents the chance to avoid prosecution (and thus the possibility of the death penalty) if they would work as British double-agents. Agents who agreed to this were supervised by MI5 in transmitting bogus "intelligence" back to the German secret service, the Abwehr. This necessitated a large-scale organisational effort, since the information had to appear valuable but in actual fact be misleading. A high-level committee, the Wireless Board, was formed to provide this information. The day-to-day operation was delegated to a subcommittee, the Twenty Committee (so called because the Roman numerals for twenty, XX, form a double cross).
The system was extraordinarily successful. A postwar analysis of German intelligence records found that of the 115 or so agents targeted against Britain during the war, all but one (who committed suicide) had been successfully identified and caught, with several "turned" to become double agents. The system played a major part in the massive campaign of deception which preceded the D-Day landings, designed to give the Germans a false impression of the location and timings of the landings Operation Mincemeat.
The Prime Minister's personal responsibility for the Service was delegated to the Home Secretary Maxwell-Fife in 1952, an arrangement that persists to this day. A directive issued by the Home Secretary set out the Service's tasks and the role of its Director General but it was not put on a statutory basis until 1989, when the Security Service Act was introduced. In fact, it was not until the end of the 1980s that the government admitted the Service's existence, although it was hardly a secret by that time. The Service has recruited openly through newspaper advertisements since 1997 and has had an Internet website since around 2000. The current Director-General is Eliza Manningham-Buller.
The post-war period was a difficult time for the Service, which conspicuously failed to detect the "Cambridge Five" spy ring and attracted much criticism as a result. It also faced an ongoing challenge from the Soviet KGB, which was extremely active in Britain, and from the rise in Irish and international terrorism. The Service was instrumental in breaking up a large Soviet spy ring at the start of the 1970s, with 105 Soviet embassy staff known or suspected to be involved in intelligence activity being expelled from the country in 1971. The growing threat of terrorism led to the Service's attention increasingly shifting to monitoring Republican and Loyalist terror groups in Northern Ireland and collaborating with other countries' agencies to combating international threats.
The Service was, however, severely embarrassed in 1983 when one of its officers, Michael Bettaney, was caught trying to sell information to the KGB. He was subsequently convicted of espionage. The Service also faced controversy when it emerged that it was monitoring trade unions and left-wing politicians; Labour Prime Minister Harold Wilson was convinced that it was conspiring against him, and the Labour Home Secretary Jack Straw discovered that the Service for which he was responsible had kept a file on him since his days as a student radical. (In his book "Spycatcher", the former Security Service officer Peter Wright claimed that up to 30 members of the Service had plotted to undermine Wilson; this allegation was exhaustively investigated and it was concluded, as stated publicly by Ministers, that no such plot had ever existed, and Wright himself finally admitted in an interview with BBC1's "Panorama" programme in 1988 that his account had been unreliable.)
Even inside the Service itself there were problems. Many defectors told of a high-level penetration in existence. Peter Wright and many other colleagues believed that all the facts pointed the former Director-General himself, Roger Hollis. The Trend inquiry of 1974 cleared Hollis of that accusation. Subsequently, the evidence of the former KGB officer Oleg Gordievsky confirmed this judgement.
The Security Service's role in counter-terrorism
The end of the Cold War—and even more the start of the "War on Terror"—reinforced the shift towards international collaboration against terrorism. After a bitter struggle with the Metropolitan Police Special Branch, MI5 took responsibility for leading the investigation of all Irish republican activity in Great Britain. It has proved itself to be extremely successful in infiltrating the IRA, with Service operations (working closely with many police Special Branches) leading to 21 convictions for terrorism-related offences between 1992 and 1999. Some commentators have suggested that MI5's ability, aided by high technology, to infiltrate and monitor IRA activities was one of the major reasons for that organisation's decision to participate in the Northern Ireland peace process, although MI5 had been waging a war of wits against republican paramilitary groups since the early 1970s. MI5 do not tackle Loyalist paramilitary groups, such as the UDA, UVF and LVF, with as many resources, as most of their activities are confined to Northern Ireland. However, this looks set to change, as it was announced in March 2005 that MI5 is to take charge of all security intelligence work in Northern Ireland from 2007.
In 1996, new legislation formalised the extension of the Security Service's statutory remit to include supporting the law enforcement agencies in the work against serious crime. This aroused some controversy at the time, as it was seen by civil libertarians as a worrying evolution into a quasi-"secret police" function, as well as an intrusion onto the jealously-guarded turf of other law enforcement agencies. However, it takes a reactive, not self-tasking, remit acting at the request of law enforcement organisations. With the rise of Islamic militants, this area of work is decreasing, and may be passed back to Special Branch or to a newly-created law enforcement organisation.
MI5 is now at the forefront of the battle against terrorism in Britain. Numerous raids against suspected militants, and the internment of key suspects in HM Prison Belmarsh in London, have been credited to Security Service intelligence. It has also been reported that Security Service officers have been involved in interrogations of British terrorism suspects interned at the United States' military base at Guantanamo Bay in Cuba and perhaps also Diego Garcia.
- Special Branch
- Spooks — a BBC television drama about the work of a group of MI5 agents, which airs in the United States on the A&E Network as MI-5 (sic).
- Central Intelligence Agency - US
- Australian Security Intelligence Organisation (ASIO)
- Canadian Security and Intelligence Service
- Joint Terrorist Analysis Centre