An "assistant commissioner" is a person who helps and supports a commissioner in their work and responsibilities. They play a supportive role and assist the commissioner in various tasks and duties. Full definition
According to it, Section 2 (1) of the Act also provides that the Commission shall consists of a chairman who shall be the chief executive and accounting officer of the commission and serving or retired member of any government security or law enforcement agency not below the rank of assistant commissioner of police or equivalent. (punchng.com)
Brian Paddick, former deputy assistant commissioner for the Metropolitan police, has initiated judicial review proceedings against his former force over the phone hacking row. (politics.co.uk)
Brian Paddick, a former deputy assistant commissioner at Scotland Yard who is also taking the police to court, suggested that his former colleagues» decision to cut short their original investigation may have been influenced by their links with the News of the World. (theguardian.com)