No order of major punishment shall be passed on a member of the service (other than an order based on facts which have led to his conviction in a criminal court) unless he has been informed in writing of the grounds on which it is proposed to take action and has been afforded an adequate opportunity of defending himself. The grounds on which it is proposed to take action shall be reduced to the form of a definite charge or charges, which shall be communicated to the persons charged together with a statement of the allegations on which each charge is based and of any other circumstances which it is proposed to take into consideration in passing orders on the case. He shall be required, within a reasonable time to put in a written statement of his defence and to state whether he desires to be heard in person. If he so desires or if the authority oral evidence shall be heard as to such of the allegations as are not admitted, and the person charged shall be entitled to cross-examine the witnesses, to give evidence in person and to have such witnesses called, as he may wish, provided that the officer conducting the inquiry may, for special and sufficient reason to be recorded in writing, refuse to call a witness. The proceedings shall contain a sufficient record of the evidence and statement of the findings and the grounds thereof.