MI5 Between The Wars
The years immediately after the First World War saw MI5's size being reduced drastically as a result of post-war cost-cutting. The Service's very existence came under threat for a time, but by the start of the 1930s it had gained new importance in countering communist and fascist subversion in the UK. It also played a leading role in countering Soviet espionage and obtaining information on Nazi Germany.
The inter-war years
MI5's fight for survival after World War I and its penetration of Nazi Germany's London embassy
The Soviet threat between the wars
How MI5 countered Soviet intelligence activities in the UK
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MI5 Director General Ken McCallum gave his annual threat update at Thames House on 14 July 2021.
The first elements of the new Counter Terrorism Operations Centre (CTOC) in London have been unveiled.
To pay our respects, MI5 is flying the UK and US flags together in the entrance of Thames House, our London HQ