Contact Us

There are different ways to contact MI5 depending on the nature of your message or enquiry. Please carefully consider the best way to contact us and whether MI5 is the correct organisation to contact.

If your information relates to an immediate threat to life or property, please contact the police by calling 999. You can call the police in confidence on 0800 789 321. 

To knowingly provide false information to the police is a criminal offence which may result in a prosecution or imprisonment.

MI5 is not a law enforcement agency and we do not investigate matters that do not involve threats to national security. If you have information about criminal activity that is not related to national security, please contact your local police force

You can also call Crimestoppers on 0800 555 111.

If a crime is currently happening or there is an immediate threat to life, please phone 999.

MI5 work with the police to disrupt threats to national security, such as terrorism or state threats. If your report relates to criminality, please contact your local police.

If you know of information that you think is related to a national security threat (such as terrorism or state threats), you can send us information through our online contact form. You can remain anonymous if you wish. Your message will be sent securely. You will receive an automated acknowledgement when you have sent your message. All messages will be read, and we take these messages seriously, but we cannot promise to respond to all of them. Where we receive information that is not related to national security, we may pass this on to the relevant police force. This may cause a delay to this information being processed, so you should contact the police in the first instance if the information you have does not relate to national security matters.

You can contact us to report National Security concerns by telephone via: 

  • 0800 111 4645 (free telephone number) 
  • +44 (0)20 7930 9000 (standard or international call rates will apply) 

Do not use this phone line for other reasons, such as making general enquiries or to ask about recruitment issues. 

Your safety and security is our priority. We will never use these numbers to call you back. Do not answer calls from this number and do not share any personal information or banking details. 

You can also write to us using the following address. Written correspondence posted in the UK may take up to a week to reach us. 

The Enquiries Desk      
PO Box 3255     
London     
SW1P 1AE

If you contact us, we will treat your information and any personal details in confidence unless you tell us otherwise, or exceptionally if there is a need to share it with appropriate parties such as the police. Please see our privacy policy for more information. 

If you are unsure whether your information is related to national security, please 

If you have a query about recruitment, please use the contact details provided elsewhere on this page.

If you have a question about applying for a job with MI5, the careers pages of our website may answer your questions. 

If you still need to contact us about recruitment, including because you are having problems applying for a job with MI5 or accessing your online application, please contact the recruitment office by email or telephone:

MI5 does not have a press office. 

If you work in the media and would like to ask about intelligence matters, MI5 or the National Protective Security Authority, please contact the Home Office press office.

We release files to The National Archives periodically. To search or access these files, please contact The National Archives. 

You can ask us whether a member of your family used to work for MI5. If they did, we may be able to share some information about their work. In line with the release of information to The National Archives, information from our files will only be shared if it is at least 50 years old and to do so would not damage national security. 

If 50 years have passed, to make a request, please write to us using the address below including a copy of your family member’s death certificate (this requirement is waived if the family member would be 110 or older if still alive) or their written consent. 

The Enquiries Desk    
PO Box 3255   
London   
SW1P 1AE

MI5 is not subject to the Freedom of Information Act. Therefore we will not provide information in response to requests referencing the Act.

Under data protection law, individuals have certain rights over their personal data. These rights are set out in the Data Protection Act 2018. Exemptions apply where they are required to safeguard national security. 

Individuals have the right to ask for copies of their personal data, sometimes known as a Subject Access request (SAR). We make a £10 charge for such requests. 

If you would like to make a SAR, please write to the address below and include a cheque or postal order for £10 made payable to ‘SAR Account’ as well as proof of identity (e.g. a photocopy of your passport or driving licence) and proof of your current address (e.g. a copy of a current utility bill) which is less than three months old and includes your full name and address. This is to ensure we do not release information to a third party. 

The Data Controller 
PO Box 3255  
London  
SW1P 1AE

We consider case-by-case whether it is necessary to rely on the national security exemption in response to a SAR. Where we decide it is, the requester has a right of appeal to the First-tier Tribunal. A person who is dissatisfied with MI5’s response to a SAR has a right to complain to the Information Commissioner.

The Environmental Information Regulations (EIR) allow the public to request access to information about the activities of public authorities which relate to the environment. MI5 is subject to the EIR, although exemptions can apply when necessary (to protect national security, for example). We will consider case-by-case whether an exemption applies. Submit EIR requests through our contact form.

If you wish to make a complaint about MI5, please contact the Investigatory Powers Tribunal.

The Cinquefoil Trust, MI5’s permanent charity, was established to support current and former members of MI5, their dependents and family members through financial difficulties. All current and former members of staff are welcome to apply for assistance. 

If you are in need of support and think you may be eligible for the Trust’s help, please write to: 

Cinquefoil Trust   
PO Box 3255  
London  
SW1P 1AE

Find out more about the Cinquefoil Trust

We often receive letters from children asking about MI5 or telling us about their career ambitions for the future. We try to respond to as many as we can. If you would like to send us letters like this, please write to: 

The Enquiries Desk   
PO Box 3255  
London  
SW1P 1AE

If you wish to give us feedback or make a general enquiry that has not been answered by the information on this site, you can get in touch using the contact form or write to:

The Enquiries Desk  
PO Box 3255  
London   
SW1P 1AE

All messages will be read, but we cannot promise to respond to all of them. There are also restrictions on what information we can provide, so if we do respond we may not be able to provide you with the information you request.