 All Metropolitan Police officers in uniform below the rank of Inspector are required to have their collar numbers on display at all times.It is increasingly common for higher ranks to display their warrant numbers on their epaulettes in addition to their rank.From 2017 to 2019 the Metropolitan Police Service reformed the organisational structure of Frontline Policing from the existing 32 Borough Operational Command Units (BOCUs) into 12 new Basic Command Units.