The years between 1929 and 1939 were a time of political uncertainty in Britain, marked by economic crises, rising extremist movements, and global instability.

The Emergence of Political Extremism

Communism in Britain

The Communist Party of Great Britain (CPGB), founded in 1920, remained relatively small during the interwar years. However, economic hardship after the Wall Street Crash of 1929 and the Great Depression gave the movement some appeal among industrial workers. The CPGB was closely tied to the Soviet Union, particularly through the Comintern, and often took direction from Moscow.

Despite its ambitions, the CPGB never gained significant electoral support, rarely polling above 0.2% of the national vote. Instead, it exerted influence through:

• Supporting trade union activism during strikes.

• Campaigning against unemployment through organisations such as the National Unemployed Workers’ Movement.

• Playing a visible role in anti-fascist demonstrations, particularly in London’s East End.

The party’s loyalty to the Soviet Union often limited its popularity, as fears of revolutionary violence alienated the wider electorate.

Mosley and the British Union of Fascists

Perhaps the most prominent extremist movement in interwar Britain was led by Sir Oswald Mosley, a former Labour and Conservative MP. In 1932, Mosley founded the British Union of Fascists (BUF), inspired by Mussolini’s Italy.

The BUF gained momentum by capitalising on:

• Disillusionment with mainstream parties after the economic crisis.

• Promises of a strong leader to combat unemployment.

• Anti-Semitic propaganda, which became increasingly central to its message.

At its peak, the BUF may have had up to 50,000 members, attracting some support among the middle classes and disaffected youth. However, violent clashes—most notably the Battle of Cable Street (1936), where anti-fascist demonstrators halted a BUF march in London—damaged its credibility. The 1936 Public Order Act, banning political uniforms and paramilitary-style marches, further curtailed its activities.

First-page scan of the Public Order Act 1936. The Act curtailed extremist street politics by banning political uniforms and regulating processions and meetings. Presenting the statute helps students connect specific legal provisions to changes in BUF tactics and public order. Source

Mosley’s admiration for Hitler and close alignment with Nazi Germany during the late 1930s caused widespread distrust, limiting his political impact.

Other Extremist Currents

Although Communism and Fascism were the most visible forms of extremism, smaller movements existed, including:

• Far-right groups like the Imperial Fascist League, though these remained marginal.

• Leftist currents within the Labour movement advocating stronger ties with the Soviet Union.

These groups, however, never came close to destabilising Britain’s parliamentary democracy.

The Impact of Foreign Affairs on Domestic Politics

The Rise of Fascist Powers in Europe

Britain’s domestic politics were deeply shaped by the international situation. The 1930s saw the aggressive rise of Hitler’s Germany, Mussolini’s Italy, and the consolidation of Stalin’s Soviet Union. These developments influenced British debate on rearmament, appeasement, and national defence.

Foreign affairs impacted domestic government in several key ways:

• Appeasement Policy: Prime Minister Neville Chamberlain’s strategy of avoiding conflict through concessions to Germany divided public opinion.

Neville Chamberlain holds aloft the Anglo-German declaration on his return from Munich, 30 September 1938. The image illustrates the political drama around appeasement and why it polarised British opinion. It also foreshadows how European crises increasingly set the agenda for domestic policy. Source

• Spanish Civil War (1936–1939): Britain officially pursued non-intervention, but the conflict became a rallying point for extremists. Communists strongly supported the Spanish Republic, sending volunteers to the International Brigades, while some fascist sympathisers admired Franco’s Nationalists.

• League of Nations Crisis: The failure of collective security, highlighted by Japan’s invasion of Manchuria (1931) and Italy’s invasion of Abyssinia (1935), undermined faith in international cooperation and fostered demands for stronger defence policies.

National Security and Public Opinion

The growing threat of war had domestic consequences:

• Rearmament became a major issue, with significant debate over the scale and timing of military expenditure.

• Air Raid Precautions (ARP) and civil defence planning began to emerge by the late 1930s, reflecting public concern about aerial bombardment.

• Political divisions deepened within the Conservative Party, with figures like Winston Churchill warning against the dangers of appeasement.

Extremism and Foreign Influence

The influence of foreign regimes directly affected extremist politics at home.

• The BUF was inspired and funded in part by Italy and Germany, while also adopting their violent methods.

• The CPGB drew ideological and organisational strength from the Soviet Union, with Moscow dictating much of its strategy.

• Both movements, however, were weakened by their reliance on foreign models that many Britons viewed with suspicion.

Government Response to Extremism

British governments in the 1930s took several measures to limit the threat of extremism:

• Public Order Act (1936): Restricted the activities of the BUF, banning uniforms and empowering police to regulate marches.

• Increased surveillance of extremist organisations by MI5 and the Special Branch.

• Restrictions on political broadcasting and publications designed to curb radical propaganda.

While neither fascism nor communism became mass movements in Britain, their presence highlighted discontent during economic crisis and revealed the impact of foreign ideologies on domestic affairs.