To hold security clearance, you must go through a process called national security vetting, which is a series of background checks to assess how appropriate it is to give you access to sensitive information, assets and equipment. This is a necessary step toward ensuring you can maintain the objective ethical standards, integrity, and professionalism they require of all their officers.

When approaching this question, or the vetting interview itself, it is advisable to be completely honest. The Border Force's website states that even if there are "aspects of their lives that they are ashamed or embarrassed to tell us about. Usually, these are of little or no security significance. They will generally not stop or restrict the granting of a security clearance. The Vetting Officer will be open-minded and is not there to make moral judgements about people's lifestyles. They will only be interested in assessing potential security risks. It is essential, therefore, that you are open and honest at all stages of the interview process."

At the interview, a vetting officer will attempt to build as complete a picture of you as possible. The purpose of this is so they can make an informed assessment of whether you will be able to "cope with access to sensitive information or assets at the highest levels and will not become a security risk and a threat to national security." Some of the key themes they assess include: "Your loyalty, honesty and reliability, and identifying any vulnerabilities that could lead you to being bribed or blackmailed, your wider family background (relationships and influences), past experiences of drug taking (if any), financial affairs, general political views, foreign travel, foreign travel, and hobbies."