"who knows there may even be civilian Chief Constables."
Already happened.
Civilian is made chief of nuclear police force - Times Online
Civilian is made chief of nuclear police force
Stewart Tendler, Crime Correspondent
A senior MI6 officer has become the first civilian chief constable in Britain for more than 50 years and will head the armed force that guards nuclear power stations.
The decison to choose Richard Thompson, who was a station chief in Baghdad and worked in Kosovo, to head the 700-strong Civil Nuclear Constabulary will cause concern among police officers.
The post for a director of policing was advertised, and the Government has also been discussing introducing civilians who have management expertise or specialist skills into at least the middle ranks of the police. Mr Thompson, 46, who will earn more than £100,000, is described by the constabulary as a senior diplomat at the Foreign and Commonwealth Office.
In a statement it said that he “has extensive experience of defence and security matters, working closely with chief police officers, government and international agencies, both in the UK and overseas”.
Fraser Sampson, the executive director of the police authority for the constabulary, said that it was different from other forces because of its role. He said: “While it works closely with Home Office and Scottish forces to all relevent policing standards, the discrete and dedicated nature of its duties means that the CNC’s arrangements necessarily differ from those of mainstream policing services.”
The last civilian head of a police force was Sir Harold Simpson, a civil servant, who was made Commissioner of the Metropolitan Police in 1946
Though you will note he did have some previous and relevant experience to draw upon......... which brings us back to the "having something to bring to the party" point.