Your web browser is out of date. Update your browser for more security, speed and the best experience on this site.
Skip to Main Content ⏎.
  • To report an imminent threat call 999 or ring the Anti-Terrorist Hotline on 0800 789 321
  • Current national threat level: SUBSTANTIAL
  • Find out more

Have you got what it takes?

Can you crack our three secret missions?

Are you up to the challenge?
TA Hub
mh-bar-remote
Play secret mission
Who we are
MI5 officers are ordinary people carrying out extraordinary work in secret
What we do
MI5’s mission is to keep the UK safe from threats
Where we are
MI5 officers work across the UK and overseas to support our mission

Did You Know?

Espionage is another word for ‘spying’
An icon of a face in shadow

Espionage is the word intelligence agencies use to describe spying. It involves getting secret information through human sources (agents) or technology, such as hacking into computer systems.

We can’t shout about our successes
We can’t shout about our successes

Due to the secret nature of their work, MI5 spies can’t talk about their achievements in public. However, they can celebrate successes with their colleagues, knowing that they are some of the only people in the country to know about a threat they helped prevent.

MI5 doesn’t just protect the country from terrorism
An icon of a shield

Although protecting against terrorism is our main focus, we also protect against foreign spies operating in the UK, work against cyber-attacks, and help protect some of the UK’s most sensitive sites, like nuclear power stations.

We’re all across the world
An icon of the globe

Although our mission is to protect against threats to the UK, that includes British people, companies and Embassies in other countries. Whilst MI6 take the lead overseas, we work with them to investigate threats and keep British interests safe.

We’re the oldest intelligence agency in the world...
An icon of a scroll

MI5 has existed since 1909, making us (and MI6) the most experienced intelligence agencies around today. Back then, we were known as the ‘Secret Intelligence Bureau’, which then branched out to MI5 and MI6 in 1914.

...Even though we’ve only ‘officially' existed since 1992
An icon of the globe

MI5 was only 'officially' declared in 1992, 83 years after it was founded. Up until this time, not even the Director-General was named in public.

Latest News

View all news

We are saddened to announce that Sir Patrick Walker, Director General of MI5 between 1988-1992, died on 13 October...

October is Black History Month - an annual celebration of the history and contributions of Black people in the UK. MI5...