(b) A certificate attesting to satisfactory completion of an approved municipal police basic training program awarded by the executive director of the municipal police training council pursuant to this subdivision shall remain valid:

(i) during the holder's continuous service as a police officer or peace officer who has an equivalency certificate for police officer training or an approved course for state university of New York public safety officers issued in accordance with subdivision three of section eight hundred forty-one of the executive law; and

(ii) for two years after the date of the commencement of an interruption in such service where the holder had, immediately prior to such interruption, served as a police officer or peace officer who has an equivalency certificate for police officer training or an approved course for state university of New York public safety officers issued in accordance with subdivision three of section eight hundred forty-one of the executive law, for less than two consecutive years; or

(iii) for four years after the date of the commencement of an interruption in such service where the holder had, immediately prior to such interruption, served as a police officer or peace officer who has an equivalency certificate for police officer training or an approved course for state university of New York public safety officers issued in accordance with subdivision three of section eight hundred forty-one of the executive law, for two consecutive years or longer; or

(iv) where the holder, whose interruption in continuous service as a police officer does not exceed ten years, has satisfactorily completed an approved police officer refresher course or where a peace officer, who seeks an equivalency certificate for police officer training or an approved course for state university of New York public safety officers issued in accordance with subdivision three of section eight hundred forty-one of the executive law, has satisfactorily completed relevant police officer training courses, as prescribed by the municipal police training council.

(c) As used in this subdivision, the term "interruption" shall mean a period of separation from employment as a police officer or peace officer who has an equivalency certificate for police officer training or an approved course for state university of New York public safety officers issued in accordance with subdivision three of section eight hundred forty-one of the executive law, by reason of such officer's leave of absence, resignation or removal, other than removal for cause. 1-a. Notwithstanding the provisions of any general, special or local law or charter, the promotion of any police officer to a first-line supervisory position on or after July first, nineteen hundred sixty-seven, shall not become permanent unless such police officer has previously been awarded a certificate by the executive director of the municipal police training council created under article nineteen-f of the executive law, attesting to his satisfactory completion of an approved course in police supervision as prescribed by the municipal police training council. Any police officer who is promoted on any basis to a first-line supervisory position on or after July first, nineteen hundred sixty-seven shall forfeit such promotion unless he previously has satisfactorily completed, or within the time prescribed by regulations promulgated by the governor pursuant to section four hundred eighty-four of the executive law satisfactorily completes, the prescribed course in police supervision and is awarded a certificate by such director attesting thereto. 2. a. The term "police officer", as used in this section, shall mean a member of a police force or other organization of a municipality or a detective or rackets investigator employed by the office of the district attorney in any county located in a city of one million or more persons who is responsible for the prevention or detection of crime and the enforcement of the general criminal laws of the state, but shall not include any person serving as such solely by virtue of his occupying any other office or position, nor shall such term include a sheriff or under-sheriff, the sheriff or deputy sheriff of the city of New York, commissioner of police, deputy or assistant commissioner of police, chief of police, deputy or assistant chief of police or any person having an equivalent title who is appointed or employed by a county, city, town, village or police district to exercise equivalent supervisory authority. b. The term "first-line supervisory position", as used in this section, shall mean the position or rank of a police officer next above the beginning rank of patrolman or the rank equivalent to patrolman, which requires performance of supervisory duties. 3. The provisions of subdivisions one and one-a of this section shall not apply to a city having a population of one million or more to the extent that such city has, by regulation promulgated by the governor pursuant to section eight hundred forty of the executive law, been exempted from the provisions of article thirty-five of the executive law. 4. Nothing in this section shall be construed to except any police officer, or other officer or employee from the provisions of the civil service law.