It is next contended for the respondents that, whatever the merits of the contentions based on the construction of the contract, the proper forum to agitate them would be the authorities constituted under the Act to hear and decide disputes relating to assessment of tax, that it was open to the appellants to satisfy those authorities that there have been no sales such as are liable to be taxed, that indeed they were bound to pursue the remedies under the Act before they could invoke the jurisdiction of the court under Art. 226 and that the learned Judges of the High court were, therefore, right in declining to entertain the present petitions. It is true that if a statute sets up a tribunal and confides to it jurisdiction over certain matters and if a proceeding is properly taken before it in respect of such matters, the High court will not, in the exercise of its extraordinary jurisdiction under Art. 226, issue a prerogative writ so as to remove the proceedings out of the hands of the tribunal or interfere with their course before it. But it is equally well settled that, when proceedings are taken before a tribunal under a provision of law, which is ultra vires, it is open to a party aggrieved thereby to move the court under Art. 226 for issuing appropriate writs for quashing them on the ground that they are incompetent, without his being obliged to wait until those proceedings run their full course.
