Report any threats to national security - such as terrorism and espionage - to MI5 (also known as the Security Service).

What you need to know

Start now on the MI5 website

Call 999 or the police anti-terrorist hotline on 0800 789 321 to report an immediate threat to life or property.

Confidentiality

Your message will be sent over a secure internet connection. You can choose to remain anonymous or include your contact details so the Security Service can get in touch with you.

All the information you send will be treated confidentially.

Other ways to contact MI5

You can report threats by phone or in writing.

MI5
Freephone: 0800 111 4645
Telephone: 020 7930 9000
From outside the UK: +44 (0)20 7930 9000
Find out about call charges

The Enquiries Desk
PO Box 3255
London
SW1P 1AE

  • Takes around 2 minutes

Get started on the MI5 website

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Please don't include any personal or financial information, for example your National Insurance or credit card numbers.