been made has failed to contest the claim, the Tribunal may, for reasons to be recorded in writing, implead the insurer and in that case it is permissible for the insurer to contest the claim also on the grounds which are available to the insurer or to the persons against whom the claim has been made. Thus, unless an order is passed by the Tribunal permitting the insurer to avail the grounds available to an insured or any other person against whom a claim has been made on being satisfied of the two conditions specified in section 170 of the Act, it is not permissible to the insurer to contest the claim on the grounds which are available to the insured or to a person against whom a claim has been made. Thus, where conditions precedent embodied in section 170 are satisfied and the award is adverse to the interest of the insurer, the insurer has a right to file an appeal challenging the quantum of compensation or negligence or contributory negligence of the offending vehicle even if the insured has not filed any appeal against the quantum of compensation. Sections 149, 170 and 173 are part of one scheme and if we give any different interpretation to section 170 of the 1988 Act, the same would go contrary to the scheme and object of the Act." (emphasis added)