The Security Service (MI5) is responsible for protecting the United Kingdom against threats to national security.

We also provide security advice to a range of organisations in the public and private sectors, and work against the proliferation of weapons of mass destruction.

Our statement of objectives and values explains the Service's responsibilities in more detail, and outlines the civic values that we follow in performing our duties.

As our resources are limited, it is essential that we use them effectively so that we can achieve the greatest impact against the most serious threats.