MI5 - the British Security Service Content from the guide to life, the universe and everything

MI5 - the British Security Service

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MI5, or The Security Service to give it its proper name, is a part of the intelligence community in the UK, and they work closely with GCHQ, MI6 and the police. As with GCHQ, MI5 is a civil service department coming under the Home Office (GCHQ comes under the Foreign & Commonwealth office). MI5 has had a long and colourful history, most of which is only just coming into the public eye - some of it is good, though some of it the Security Service would rather forget.


At the beginning of the 20th Century, Germany was a fairly new nation; she was expanding her military might and Britain was keeping a wary eye on her. By 1909 it was realised by the Imperial Defence committee that Germany was gathering intelligence on the Royal Navy. To counter this, in October of the same year, Captain Vernon Kell, of the Army, and Captain Mansfield Cumming of the Royal Navy, formed the 'Secret Service Bureau'. Shortly after this the 'SSB' was split into two arms: one arm headed by Kell (by this time known simply as 'K') who was in charge of counter-espionage at home; the other headed by Cumming (by this time known simply as 'C') who was tasked with gathering intelligence from overseas. Kell's group was later to become MI5, and Cumming's group MI6. It is said that even today the heads of MI5 and MI6 sign documents 'K' and 'C' respectively.

Initial Success

Between 1909 and 1914 Kell's branch of the 'Secret Service Bureau' was responsible for the capture of more than 30 spies; this is no mean feat when you take into account that Kell's staff, including Kell himself, totalled ten people.

In 1916 the 'Secret Service Bureau' came under the Directorate of Military Intelligence, and as previously stated, Kell's arm was named MI5 and Cummings group MI6. MI5 and MI6? As you have probably guessed there were other departments within the Directorate of Military Intelligence:

  • MI1 - Codebreaking (later GC&CS, then GCHQ)
  • MI4 - Aerial reconnaissance
  • MI7 - Propaganda section
  • MI8 - Telegraph1 censorship
  • MI9 - Postal censorship

This is not an exhaustive list, and none of these departments exist today; they have either been disbanded, or amalgamated into other departments.

World War I saw a large increase in the responsibilities of MI5. Not only was it now in charge of counter-espionage at home, but also throughout the British Empire. It also took on the role of vetting employees of 'war factories', and advising the government on alien2 policy. By the end of the war in 1918, in which time another 35 spies had been captured, MI5 had somewhere in the region of 850 employees.

Between the Wars

The war was over and after the treaty of Versailles Germany no longer posed a threat; however, this did not mean an end for MI5, just a new threat, Communism. After the Bolshevik Coup d'état in 1917, the British government saw itself as being under threat of subversive tactics from the new Soviet Union. They also saw a threat of sabotage to military installations; this was to be MI5's new focus. The rise of Hitler and the Nazi Party in Germany also saw the rise of a new threat to British national Security - subversion from fascists.

In 1924, MI5 came into possession of a letter written by Grigory Zinoviev chairman of the 'Comintern'3, this letter urged British communists to promote revolution. Kell was convinced this letter was genuine and showed it to Prime Minister Ramsay MacDonald. It was agreed that the letter would be kept secret but it somehow got leaked to the press, who published it a few days before the general election. It was partially down to this that Ramsay MacDonald's Labour party lost the election. Shortly afterwards it was claimed that MI5 agents had forged the letter and leaked it to the press.

In 1931, MI5 was formally put in charge of British national security (except for threats from Irish militants and anarchists) and was renamed 'The Security Service'. This is the name it goes by today, although it is still more commonly known as MI5. It is around this time that MI6 became 'SIS' or the 'Secret Intelligence Service'. Again this is the name the organisation is known by today, however it is still better known as MI6.

World War II

The beginning of World War II was not a good time for MI5. It was severely understaffed (just 30 operatives plus six surveillance operatives), it had just been evacuated to Blenheim Palace and its workload had been increased. To top all this off, in September 1940 it lost most of its records to a German bombing raid.

After all these setbacks, in early 1941 David Petrie was appointed as the first ever Director General. He was given the resources to build a more substantial Security Service able to fulfil its role.

Despite the early setbacks in World War II, MI5 performed extremely well. It transpired through German intelligence reports captured in 1945, that MI5 had successfully identified and captured all 115 German spies sent to Britain. Furthermore, Germany was unable to recruit a single British person sympathetic to the Nazi Party.

Some of the captured German agents were employed by MI5 to feed false information back to Germany; this is the infamous 'double agent' scheme. There is a known case of two double agents, who were instructed by MI5 to give information to Germany that led to a food store being bombed by the Germans. The reason was so that the Germans didn't suddenly realise their agents had changed sides, which they would have done had information suddenly stopped being fed to them. The use of double agents was a great help in the preparations for D-Day.

World War II - 1990

The end of World War II saw MI5 focusing most of its energies on the subversive threat from the USSR. This included the vetting of all peoples employed in 'work vital to national security'. The need for MI5 in this role was validated with the case of the Cambridge Spies. By the early 1950s, staffing levels had reached around 850.

In 1952, Prime Minister Winston Churchill passed on the responsibility of overseeing MI5 to the Home Secretary. MI5 to this day still comes under the Home Office.

The 1960s saw a lot of action for MI5. To start with, there was the 'Portland Spy Ring'; Harry Houghton was an ex-Royal Navy serviceman, who had been recruited by the KGB whilst working in Warsaw in the 1950s. In the early 1960s, he was working at the Underwater Detection Establishment in Portland. He and his partner Ethel Elizabeth 'Bunty' Gee were passing on British naval secrets to their KGB controller 'Canadian businessman Gordon Lonsdale', real name Colonel Conon Molody of the KGB. After almost a year of MI5 surveillance all three were arrested, during one of their meetings.

In 1961, John Profumo was the Secretary of State for War. At a party, he was introduced to a young lady by the name of Christine Keeler. Although Profumo was a married man, he fell for young Miss Keeler and they had an affair. This in itself doesn't sound any worse than anything any other politician has done, but what made the 'Profumo Affair' so important was that Miss Keeler had also had an affair with Eugene Ivanov, a Soviet spy. Not only that, she also lived with Stephen Ward who was accused of passing on documents to the Soviets. What does this have to do with MI5? It was Lord Denning's report into the 'Profumo Affair' that brought the role of MI5 to the public eye for the first time.

The 1970s saw plenty of action as well. In 1971, a total of 105 Soviets were kicked out of Britain for being suspected of being spies. Towards the end of the '70s saw the peak of the Cold War dying off, and with this the threat of subversion subsided slightly. However, there was a relatively new threat for MI5 to focus on, terrorism.

The early 1980s saw terrorist actions such as the Iranian Embassy siege in London. These events tested MI5 in new ways, and it was due to these actions that MI5 was at the forefront of developing an international network with other nations to help combat global terrorism.

In 1989, the Security Service Act was introduced. This gave the Security Service a legal standing within the government for the first time since it was first established in 1909. It also meant that MI5 became a lot more accountable for its actions. It could no longer bug somebody's house/business or tap somebody's telephone line without a warrant; these are just a couple of the clandestine things MI5 now has to be wary of carrying out, things that it used to carry out with some degree of freedom.

The 1990s

The fall of the Berlin Wall in 1989 saw the beginning of the end for the USSR, and in 1991 the Cold War was officially over. The end of the cold war saw a decrease in the threat of subversion to the point where it was negligible. This meant that MI5 had resources available for other areas. Due to this and MI5's experience in gathering intelligence on Irish militants abroad, the Metropolitan Police officially handed over the intelligence effort against Irish terrorism on the UK mainland in 1992. Between 1992 and 1999, MI5, working closely with UK police, managed to prevent a few intended terrorist attacks, including large-scale city centre bomb attacks. They also managed to bring 21 convictions against Irish militants for terrorist activities.

In 1996, new legislation gave MI5 a totally new field to work in. This is the field of serious crime. MI5 will, when requested, assist UK Police in serious crime cases such as drugs/weapons trafficking, excise fraud and illegal immigration rings.

Hall of Fame

The following section gives a list of some of the people who have worked for MI5 and the significant roles they have played.

Vernon Kell

Born in 1873, Vernon Kell was educated at Sandhurst military academy, after which he joined the British Army. Kell was a brilliant linguist; he could speak German, Italian, French and Polish, and he also went on to learn Russian and Chinese. Due to his linguistic skills Kell became an interpreter for the army. He saw service in the Boxer Rebellion, and spent some time as an intelligence officer.

By 1909, Kell was a Captain of the South Staffordshire Regiment; he also worked for the German section of the war office and it was through this post that he came to co-found the Secret Service Bureau with Captain Cumming of the Royal Navy. Vernon Kell remained the head of MI5 until 1940.

David Petrie

As previously mentioned, David Petrie became Director General in 1941, and did a very good job of rebuilding MI5. In 1945 it had been suggested that the responsibility of tracking Soviet spies and subversives should be handed over to Scotland Yard's Special Branch. David Petrie fully opposed the police being in charge of this task. In a letter to the Home Office, he attacks the police's ability to perform this role. After this the role is kept within MI5.

Roger Hollis

Roger Hollis joined MI5 in 1939, and worked on the Russian desk. In 1953 he made it to Deputy Director General and by 1956 he was Director General. What's so special about Roger Hollis? He was accused of being a Soviet mole4 from the beginning, and the evidence against him although circumstantial is quite weighty.

Take the case of Klaus Fuchs, a German refugee who came to Britain in 1933, who was also a member of the communist party. This fact was even passed on to the British by German police but never fully looked into. Fuchs ended up working on the Manhattan project in Los Alamos, which developed the world's first atomic bomb. In 1950 he confessed to being a Soviet spy. Whenever Fuchs was called in to question one of his strongest supporters was Roger Hollis.

Then there is the case of 'Kim' Philby one of the Cambridge spies. Philby was a close friend of Roger Hollis. In 1963, when Philby was about to be pulled in for his spying, he was tipped off and he managed to defect to the Soviet Union. One of the few people who could have tipped him off was believed to be Roger Hollis.

Finally, there is the fact that in the time Roger Hollis was Director General of MI5 (1953-1965), there was a growing belief that there was one Soviet spy that had not been identified by MI5 because of interference and protection from within. All spies captured in Britain during this time were identified by defectors to the CIA, but many of the defectors intimated that there was still one spy remaining. Shortly after Hollis retired there was an investigation and he was found to be innocent of any allegations that the spy was in fact himself. It was concluded that the suspicion came as a result of paranoia within the department, fuelled in part by the Soviet Union, which it was believed had probably been spreading rumours and disinformation in order to undermine MI5.

Peter Wright

Peter Wright was an MI5 officer until his retirement in the early 1980s. Shortly after he left the service, he wrote a book called Spycatcher. In this book he made quite a few revelations about the workings of MI5; he even revealed the existence of a supposed plot by members of MI5 to overthrow the Prime Minister Harold Wilson. This allegation was investigated and found to be false. Wright later claimed that some of his book was dramatised for effect, and some critics accused Wright of acting out of bitterness over an unresolved issue with his pension. Though Spycatcher has largely been discredited, the lengths the British Government went to in order to silence Wright5 suggested to many that there was more truth within the book's pages than many were prepared to admit.

Stella Rimington

Stella Rimington managed two firsts within MI5. Firstly she was the first ever female Director General; secondly her appointment as Director General was the first to be publicly announced. Having worked in MI5 since the late 1960s, she was Director General between 1992 and 1996. Shortly after she retired she wrote her memoirs. At first she met stiff resistance from government on letting her publish them, but because this was happening in the public eye government relented with a compromise. They requested that certain parts of the memoirs were altered and some removed altogether on the grounds of National Security. Despite the fact that her book was submitted and approved by various offices within the government, on its eventual publication the same offices denounced her work as irresponsible, an irony that did not escape Rimington herself. After this fiasco, Dame Stella Rimington openly criticised the Official Secrets Act6 saying it was outdated and needed replacing.

David Shayler

David Shayler is an ex-MI5 operative who left in 1996 after stealing several 'secret' files that he claimed were in the public interest to see. In 1997, he released details to a British newspaper, including a financial connection between Libya and the IRA, an MI6 plot to kill Colonel Gaddafi in 1996, the fact that MI5 kept files on some prominent politicians and evidence that he believed showed MI5 could have prevented the 1994 bombing of the Israeli embassy in London. David Shayler then moved to France with girlfriend Annie Machon also an ex-MI5 officer. France refused to extradite David Shayler, but he returned to the UK of his own free will in 2000. In October 2002 Shayler was sentenced to six month's imprisonment for three charges of breaking the official secrets act. He was released after just seven weeks.

David Shayler maintains he released the information in the public's interest to point out MI5's shortcomings. The government argues there are official channels for whistle-blowing, that don't include the press, or the public.

MI5 Today

MI5 is currently staffed by around 3,800 people, and it still carries on in pretty much the same role that it did towards the end of the 1990s. The main areas it now covers are:

  • Espionage
  • Terrorism
  • Serious Crime
  • Proliferation


Although communism ended in Russia in 1991, and she is now a 'friendly' state, she has been proven in later years, particularly since 1997, to be actively gathering intelligence abroad including from Britain.

The other main threat comes from China. Although the majority of the intelligence China seeks on Britain can be pieced together with information available in the public domain, the rest has to be got through clandestine measures.

So, more than a century on and MI5 is still actively working in counter-espionage, as it was first set up to do, albeit faced with a different 'enemy'.


MI5 has been at the forefront of fighting terrorism since it first became a major threat in the 1970s. It has had many successes in fighting terrorism along with some failures. The terrorist attack on the World Trade Center, which has come to be known simply as 9/11 changed everything in the world of terrorism. MI5 now faces a new kind of terrorist, a terrorist who doesn't plan an escape route into their action, a terrorist who doesn't want to negotiate the freedom of some political prisoner, a terrorist who isn't willing to negotiate his own surrender, a terrorist who works in such a tight-knit group that it is almost impossible for MI5 to get an operative into the terrorist cell.

How MI5 and indeed the world at large cope with this new breed of terrorist and handle the 'War on Terrorism', only time can tell.

Serious Crime

MI5 will not investigate serious crime cases on its own, and only becomes involved in such cases when asked to do so by the police or Customs and Excise. Even then MI5 will only become involved if it believes its particular skills will be of benefit to the case. Since 1996, MI5 has contributed to cases that have seen over 100 arrests and the seizure of more than £20,000,000 of class A drugs7.

It is worth mentioning at this point that MI5 has no executive powers: MI5 operatives cannot arrest anyone. If MI5 has information that should lead to arrest, this is passed on to the police to do. The police also provide MI5's evidence to court.


The fall of the USSR saw instability throughout the ex-Soviet bloc, as can be seen in places such as Chechnya and former Yugoslavia. This instability has increased the availability of ex-Soviet weapons technology, especially nuclear, biological and chemical warfare, on the black market. Unfortunately, this material is falling into the hands of terrorists and countries which are pursuing weapons programmes that break international non-proliferation treaties, treaties which are designed to keep these weapons to a minimum. Britain has a lot of the technology sought after by these 'rogue' states; it is the job of MI5 to make sure they don't get their hands on it.

This is done through a number of methods including vetting of certain foreign nationals who come to the UK to study at university. British universities have access to, and help develop, a lot of this technology. Also MI5 give security advice to companies that manufacture such technologies or components that are used in these technologies.


The BBC are currently in the ninth and final series of the drama Spooks which follows a small group of people who work for MI5. Although the programme is fictional, it's reputedly as close to the real workings of MI5 as it's possible to portray in a drama series.

Further Information

More information can be bound at the following sites:

1The form of communication, not the newspaper.2Foreign nationals, not little green men.3Communist International, it was their aim to turn the world into one large Soviet union.4A person planted in an organisation to spy, not the little underground creature.5Including an expensive and ultimately unsuccessful court case in Australia.6All members of the armed forces, security services and some civil service departments sign this.7Heroin, Cocaine etc.

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