3. The members of the Board representing employers shall be nominated by the Council of the National Farmers' Union, and of the members representing workers in agriculture five shall be nominated by the Executive Committee of the National Union of Agricultural Workers and three by the General Executive Council of the Transport and General Workers' Union. If the said Council or Executive Committee or General Executive Council, as the case may be, shall fail to nominate within such period of the occurrence of any vacancy, as the Minister may direct, a person to fill such vacancy, the Minister may fill the vacancy by nominating any person whom he may consider to be fit and proper for that purpose to act as a member of the Board.