Jersey's Royal Court says the Constable of St Helier is free to choose who serves as head of the parish police. St Helier has been without a Chef de Police since February last year when Ted Gallichan stepped down.
Centenier Chris Gray - a St Helier honorary officer for 17 years - said he was entitled to take up the position.
But the Royal Court decided length of service was irrelevant since it also covered other roles in the parish's administration.
The court has advised the Constable to take length of service into consideration when choosing a new Chef de Police.
Constable Simon Crowcroft said that, although the longest serving officer had often become the head of the police, it was up to him to decide.
He said he would consult his honorary police officers before making the appointment.