4. It is only in special circumstances that it is appropriate for the Court to make an order for costs against an intervener or, at all events, an order which would have the result that an intervener pay to one of the parties more than the amount by which the costs of that party have been increased by the intervention. However, it appears to us that such special circumstances exist in the present case. As has been said, it was the Commonwealth which obtained the removal of the cause into this Court so that it could intervene and challenge the correctness of the answers favouring the respondent. It has failed in that challenge. In our view, it is appropriate that an order be made that the Commonwealth pay the costs of the respondent of the proceedings in this Court, including the costs of the present application. In so far as the proceedings in the Federal Court are concerned, the appropriate order is that the Commonwealth pay the costs of the respondent of those proceedings to the extent, if at all, to which they were increased by the intervention of the Commonwealth in that court.