Warrant Card

A warrant card is proof of identification and authority carried by police officers. The term is normally used only within the United Kingdom and in current and former Commonwealth countries. Many other countries refer to their equivalent of warrant cards simply as police credentials, commission books, or identification cards.

Warrant cards generally include a photograph of the holder, as well as the holder's name, rank, warrant number and a holographic emblem to mark authenticity. The warrant number is equivalent to a badge number in other police services; it is a unique identifier unlike a collar number (sometimes displayed on the uniform) which may change when transferring between departments or changing rank. A warrant card is sometimes displayed alongside a badge showing the service to which the officer belongs, but is increasingly commonly displayed on one ID card, with the force crest printed on it.

The language on a warrant card usually indicates that the holder is granted authority by a specific official to perform the functions of the office held, and may also indicate training to a particular level. In the UK Police personnel authorized to carry firearms may have an endorsement on their warrant card to that effect.

Police officers in plain-clothes are required to identify themselves and produce their warrant card when they are performing their police duties and exercising their police powers, so long as it is practicable to do so (i.e. not if the person they are arresting is being violent). Generally, police officers are required to produce their warrant card when requested, even in uniform, but only if it is practicable.