The dignity of Knight Bachelor is a part of the British honours system. It refers to someone who has been knighted by the monarch but not as a member of one of the organized Orders of Chivalry. Knights Bachelor are the most ancient sort of British knight, existing during the reign of King Henry III, but they rank below members in the various orders. There is no female equivalent and women deserving an honour of this rank are appointed DBE instead.
It is generally awarded for public service; amongst its recipients are all male judges of the High Court of England and Wales. Like other knights, Knights Bachelor are styled "Sir". Knights Bachelor are not entitled to use post-nominal letters after their name [1], but "Kt" (note the lowercase 't', which distinguishes it from "KT", the post-nominals of a Knight of the Thistle) is sometimes used erroneously. When the style "Sir" is awkward due to a subsequent appointment as a life peer or baronet (for example, the Baronet Sir William Boulton) recipients are sometimes exceptionally given permission to use this form of shorthand to signify that they have the additional honour.