Although the SDS’ principal remit was supposed to be public order, it is impossible to understand how and why the unit operated without understanding how the British state defined ‘subversion’. One reason for this is that, according to successive Special Branch Guidelines, they had a duty to provide MI5 with information related to subversive activity.
In 1975, subversion was defined in a speech by Labour Party minister Lord Harris:
Activities threatening the safety or wellbeing of the state and intended to undermine or overthrow parliamentary democracy by political, industrial or violent means
However, importantly, there was no criminal law which defined a subversive act. This meant that who and what were deemed subversive were entirely subjective.
Where SDS senior police managers lacked obvious public order concerns to justify spying on or infiltrating political groups, ‘subversion’ became a useful 'backstop' justification for the surveillance.
Despite this, throughout the period that the SDS operated, there was persistent uncertainty about what the term ‘subversion’ actually meant. This is reflected in the wildly differing understandings of the term by former SDS undercover officers.
In practice, state monitoring of ‘subversion’ evolved from relatively narrow concerns about Soviet Union-aligned communism to broad, catch-all surveillance that netted much of the UK’s political left.
The British state’s concern with subversion emerged from the Cold War. The Cabinet Office Communist (Home) Committee was established in 1951 and later became the Official Committee on Communism (Home). Its primary concern was the Communist Party of Great Britain (CPGB), which was regarded as the principal domestic manifestation of Soviet influence.
By the late 1960s, however, anti-Vietnam war protests, student occupations, and other manifestations of the New Left challenged the ‘official’ communism of the CPGB as the main source of concern for the surveillance state. Reflecting this shift, in 1968, the Cabinet Office renamed the committee structure Communism (Home) as Subversion (Home).
The clearest evidence of this transition appears in the Security Service paper, Subversion in the United Kingdom – Spring 1968. Where previous reports had concentrated on communist influence within trade unions, the spring 1968 assessment stated that ‘pride of place’ should be given to the ‘subversive elements’ behind recent protest demonstrations. This identified the Vietnam Solidarity Campaign (VSC), Radical Student Alliance (RSA), Trotskyist organisations, and anarchist groups as emerging concerns.
The 'Maxwell-Fyfe directive' outlined the duties and political independence of the Security Service in 1952 and also included a definition of subversion. It was not until 1963 that it was made public, when Lord Denning included it in his report on the 'Profumo Affair', saying it was to:
contemplate the overthrow of the Government by unlawful means.
A broader definition emerged during the early 1970s. Security Service and Cabinet Office papers defined subversion as ‘activities threatening the safety or wellbeing of the state and intended to undermine or overthrow parliamentary democracy by political, industrial or violent means’. This became the standard definition employed by MI5, Special Branch and government committees concerned with counter-subversion. This version was adopted by Lord Harris in a speech to the House of Commons in 1975.
This shift was significant; it no longer required evidence of criminal conduct to justify a state response. Now, the state could label as subversive any political campaigning, industrial action, and other lawful activities that officials believed threatened parliamentary democracy.
This point was later highlighted by the late Labour MP Robin Cook, who observed that:
[Lord Harris'] definition of subversion does not turn on any reference to the unlawful. It is in no way restricted to unlawful activities. It is, therefore, an invitation to the police forces that police this concept of subversion to stick their nose into any form of political or industrial activity.
Internal correspondence demonstrates that officials themselves struggled to distinguish between legitimate political activity and subversion. In 1979, Chief Constable Charles Horan acknowledged that Special Branch officers found it difficult to determine where ‘legitimate politics ended and subversion began’. A Home Office review reached a similar conclusion, noting that Special Branch officers had difficulty defining the proper boundaries of subversion and that much of their work involved monitoring lawful activity on behalf of the Security Service.
Given this lack of clarity, it is unsurprising that former SDS officers offered very different understandings of subversion during Inquiry hearings.
HN321 'Bill Lewis' regarded any 'extreme political activities' as potentially subversive and considered groups such as the International Marxist Group subversive because they believed a Marxist or Trotskyist government should replace the existing one.
HN336 'Dick Epps' stated that 'fermenting unrest on the streets and disrupting the lives of everyday people was subversive'.
HN329 'John Graham' adopted an even broader definition, describing Special Branch's role as gathering intelligence on activities seeking 'to undermine the status quo, the government of the day and the political establishment'. There were even disagreements about the same organisation: HN354 Vince Harvey (‘Vince Miller’) regarded the Socialist Workers Party as subversive, whereas HN80 ‘Colin Clark’ considered it only a public-order concern.
The SDS inherited Special Branch’s longstanding responsibility for assisting MI5 with investigations into subversion. As a result, deployments that could not easily be justified on public order grounds could instead be justified under the much broader heading of subversion. This gave the SDS an extra rationale to infiltrate and report on political groups, even where there was little evidence of criminality or serious disorder.
Organisations infiltrated by the SDS overlapped with those of interest to the subversion committees and MI5. These included the Vietnam Solidarity Campaign, Radical Student Alliance, International Socialists , People’s Democracy , Northern Ireland Civil Rights Association , anti-apartheid organisations , women’s liberation groups, anarchist collectives, Greenham Common activists and other peace campaigners. Many of these organisations posed little or no public-order threat and were engaged in entirely lawful political activity.
Documents released by the Inquiry highlight extensive liaison between MI5 and the SDS. By the late 1970s, monthly meetings were taking place, and MI5 regularly requested information about specific political organisations and activists. Intelligence gathered by SDS officers was woven into a wider system of political policing that targeted any group the state considered subversive.
Successive assessments by the Security Service and the Cabinet Office repeatedly acknowledged that industrial disputes, protest campaigns and social movements were usually driven by genuine political or economic grievances rather than by revolutionary conspiracies. Nevertheless, surveillance expanded throughout the period.
The concept of subversion evolved from a Cold War concern with Soviet Union-aligned communism into a broad and elastic category encompassing Trotskyists, anarchists, anti-war activists, anti-apartheid campaigners, peace activists, civil rights organisations, and many other groups.
Although formal definitions emerged during the 1970s, officials repeatedly acknowledged uncertainty about where legitimate political dissent ended and subversion began.
The Inquiry evidence suggests that these fluid boundaries enabled the long-term infiltration of numerous political organisations, all justified as counter-subversion. Understanding how the state defined, redefined, and operationalised ‘subversion’ deepens understanding of SDS targeting.