Introduction to the Security Service

MI5's mission is to keep the country safe. For more than a century we have worked to protect our people from danger whether it be from terrorism or damaging espionage by hostile states.

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Are you up to the challenge?

The My MI5sion challenge will put your memory and judgement skills to the test. Can you crack our 3 secret missions and pass the test?


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MI5 Director General Ken McCallum gave his annual threat update at Thames House on 14 July 2021.

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The first elements of the new Counter Terrorism Operations Centre (CTOC) in London have been unveiled.

Fact or Fiction

MI5 has a secret museum in its headquarters