1.2 Inter-war period

After this auspicious start, the history of MI5 becomes darker. It was consistently successful throughout the rest of the 1910sCenturies: 19th century 20th century 21st century Decades: 1860s 1870s 1880s 1890s 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 Events and trends Technology John Alcock and Arthur Whitten Brown make first non 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, 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, 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 has happened almost entirely without supervision; MI5 had no responsibility to Parliament, and is 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. 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.

1.3 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. 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.

1.4 Post-war

The Prime Minister's personal responsibility for MI5 was delegated to the Home Secretary 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 MI5's existence, although it was hardly a secret by that time. MI5 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. MI5 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.

MI5 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 been keeping a file on him since his days as a student radical.

Even inside the Service itself there were problems. Many defectors told of a high-level penetration in existence. Peter Wright (author of Spycatcher) and many other colleagues believed that all the facts pointed the former Director-General himself, Roger Hollis. Hollis was eventually acquitted, but many held that he was guilty up to that point.

1.5 MI5'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. MI5 was extremely successful in fighting Irish terrorism, with Service operations leading to 21 convictions for terrorist-related offences between 1992- 1999. Some have suggested that MI5's increasing 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.

In 1996, new legislation formalised the extension of MI5'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.

MI5 is now at the forefront of the battle against Islamist terrorism in Britain. Numerous raids against suspected militants, and the internment of key suspects in Belmarsh Prison in London, have been credited to MI5 intelligence. It has also been reported (and not denied) that MI5 officers have been involved in interrogations of British terrorism suspects interned at the United States' military base at Guantanamo Bay in Cuba.

2 See also

• GCHQ
• MI6
• 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.

3 External link

• Official Security Service website

UK intelligence agencies Law enforcement in the United Kingdom

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