Section 21A. The board or officer in a city or town authorized to appoint police officers for such city or town may, when so authorized, in a city having a Plan E charter, by the affirmative vote of a majority of the city council, in any other city, by vote of the city council subject to the provisions of its charter, and in a town, by a majority vote at an annual town meeting, appoint as a police cadet, for a period of full-time ''on the job'' training, any citizen resident in such city or town who is not less than eighteen nor more than twenty-three years of age or in the city of Boston any citizen resident who is not less than eighteen nor more than twenty-five years of age who meets the physical qualifications required of applicants for appointment to the police force in such city or town, and who is determined by the appointing authority to be of good moral character. Such appointment shall not be subject to the civil service law or rules; nor shall a police cadet be entitled to any benefits of such law or rules. Such appointment may be terminated by the appointing authority at any time, and shall be terminated whenever a cadet fails to maintain a passing grade in any course of study the appointing authority determines he should undertake, and when he reaches the age of twenty-five or in the city of Boston whenever a cadet fails to maintain a passing grade in any course of study the appointing authority determines he should undertake, and when he reaches the age of twenty-seven. A police cadet shall receive such compensation and such leave with pay as the appointing authority shall determine. No person shall be too old for appointment as a cadet if he or she was of qualifying age at the time of application to a cadet program. An appointment to a cadet program shall not be terminated for age unless the cadet has completed 2 years of service.

A police cadet shall maintain and file records, operate office machines, answer telephones, receive complaints, enter and index official documents, prepare routine reports, prepare and tabulate facts and figures for statistical purposes, and have similar duties of an administrative rather than an enforcement type. He shall not carry arms, nor shall he have any power of arrest other than that of an ordinary citizen. He shall be considered an employee of the city or town for the purposes of workers' compensation.

A police cadet shall not be subject to or entitled to the benefits of any retirement or pension law nor shall any deduction be made from his compensation for the purpose thereof; but a police cadet who during the period of his ''on the job training'' passes a competitive civil service examination for appointment to the police force of such city or town, and is appointed a permanent full-time police officer, shall have his police cadet service considered as ''creditable service'' for purposes of retirement, provided he pays into the annuity savings fund of the retirement system such amount as the retirement board determines equal to that which he would have paid had he been a member of said retirement system during the period of his training as a police cadet.