JOSEPH P. SULLIVAN, J.
The writ is sustained. Rule 4.49, g.(2) of the Rules and Regulations of the Department of Correction provides that in sentence institutions the disciplinary board shall consist of three members, one of whom must be a Deputy Warden. At none of the three disciplinary hearings affecting relator was such an officer present. Instead, a Captain presided as chairman at such hearing. The departmental rule that the board consist of a member who is of the rank of Deputy Warden is mandatory. The board thus was improperly constituted and its action in levying loss of good time as punishment for relator's infractions is a nullity. Inasmuch as relator's scheduled release date was June 7, 1973, calculated on no loss of good time, his discharge is ordered forthwith.