A more thorough explanation:

A Yeoman of the Guard is a member of a group of officers who are responsible for ceremonially guarding the English royal household. They are usually tall, at least six feet, and are considered to be of a high rank just below the gentry. They are also typically exempt from being arrested for civil offenses.

• During state occasions, the Yeoman of the Guard can be seen wearing their distinctive Tudor uniforms and carrying their halberds.
• The Yeoman of the Guard have been a part of the royal household since the reign of Henry VII.

These examples illustrate how the Yeoman of the Guard are responsible for ceremonial duties and have a long history of serving the English royal household.