 In September 2018, this changed and all new officers warrant numbers start EA followed by a three digit number.When a police officer or a member of staff is in a collaborative (multi-constabulary) unit or department (such as the Bedfordshire, Cambridgeshire and Hertfordshire Road Policing Unit), the PNC code, which is a force identification number, is added to the collar number to prevent confusion between officers; e.g., 41-9999 would indicate a Hertfordshire officer.These numbers are only used in paperwork and are not seen on the officer's epaulettes.