Guidance is contained in the “National Agreement on arrangements for the use of interpreters, translators and language service professionals in investigations and proceedings within the criminal justice system”. Annex C and D of the National Agreement give detailed guidance on how to source the appropriate language service professionals when a registered one is not available and how to identify the right mode of communication with a person who has a hearing impairment. Copies of the National Agreement have been placed in the Library. Additional guidance is issued in individual force areas at the discretion of the chief officer.