The rank of Knight Bachelor is a part of the British honours system. It refers to a man who has been knighted by the monarch but not as a member of one of the organised Orders of Chivalry. Knights Bachelor are the most ancient sort of British knight, existing during the reign of King Henry III (1 October 1207 – 16 November 1272), but they rank below knights in the various orders. There is no female equivalent and women deserving an honour of this rank are appointed Dames of the Order of the British Empire (DBE) instead.
Like other knights, Knights Bachelor are styled "Sir". Since they aren't knight of any order of chivalry, Knights Bachelor don't normally have a post-nominal to be rendered after their name. However, when the style "Sir" is awkward or incomplete due to a subsequent appointment recipients may sometimes use the word "Knight" or "Kt" (note the lowercase 't', which distinguishes it from "KT", the post-nominals of a Knight of the Thistle) after their name in formal documents to signify that they have the additional honour. This style is often adopted by Knights Bachelor who are also peers, baronets or knights of the various statutory orders (e.g., the Baronet Sir William Boulton, Bt, Kt).
Upon an oval medallion of vermilion, enclosed by a scroll a cross-hilted sword belted and sheathed, pommel upwards, between two spurs, rowels upwards, the whole set about with the sword belt, all gilt.
In 1974, Queen Elizabeth II issued a further warrant authorising the wearing on appropriate occasions of a neck badge, slightly smaller in size, and in miniature. In 1988 a new certificate of authentication, a knight's only personal documentation, was designed by the College of Arms.