Whether a decision of the Appellate Tribunal that an appeal to it from an award was competent under section 7 (1) (a) on the ground that it involved a substantial question of law is final and not open to question in a civil court is a point on which we do not desire to express an opinion, as in the present case, the correctness of that ,decision is challenged not collaterally or in independent proceedings, such as an application under article 226 of the Constitution as in the two cases relied on for the respondent, but by way of appeal under article 136, and it is open to us to consider as a Court of Appeal whether, in fact, the order of the Tribunal was vitiated by an error of law, and whether the (1) 104 (2) A.I.R. 1956 All. 491, 104 798 order of the Appellate Tribunal modifying it is sound.