A pocket notebook or PNB is a notebook used by police officers in the United Kingdom to officially record details and incidents while on patrol. Its use is controlled by a number of guidelines, as information entered into an officer's PNB is admissible in court, and the officer will use it to refresh their memory while giving evidence, and to support their statements. Some forces have replaced paper PNB's for ePNB's; these are electronic versions on Police Smart Phones. [1]