| Director General of the Security Service (MI5) | |
|---|---|
 | |
| Security Service (MI5) | |
| Residence | Thames House, London, UK |
| Appointer | Home Secretary |
| Term length | No fixed term |
| Inaugural holder | Vernon Kell 1909 |
| Formation | Security Service Act 1989 |
| Website | https://www.mi5.gov.uk/ |
The Director General of the Security Service is the head of the Security Service (commonly known as MI5), the United Kingdom's internal counter-intelligence and security agency. The Director General is assisted by a Deputy Director General and an Assistant Director General, and reports to the Home Secretary, although the Security Service is not formally part of the Home Office.