Officers in charge of the twelve geographical Basic Command Units are referred to as "BCU commander". However, the officers do not hold the rank of commander but instead hold the rank of chief superintendent. Prior to organisational change merging boroughs in to BCU's, officers in charge of policing each of the London's boroughs were given the title "borough commander". A previous exception to this was the borough commander of Westminster, who held the rank of commander due to the size, complexity, and high-profile nature of the borough.