The ranks of police officers are as follows (ending with the highest ranking):
Constable
Sergeant
Inspector
Chief Inspector
Superintendent
Chief Superintendent
Assistant Chief Constable
Deputy Chief Constable
Chief Constable
The rank system within the Metropolitan Police Service is slightly different, and is as follows (ending with the highest ranking):
Constable
Sergeant
Inspector
Chief Inspector
Superintendent
Chief Superintendent
Commander
Deputy Assistant Commissioner
Assistant Commissioner
Deputy Commissioner
Commissioner