The Competition Commission has recommended local authorities start competition tests in planning applications for new grocery stores after making just one change following an appeal by supermarket giant Tesco.The Commission said that following Tesco's objection, which was upheld by the Competition Appeal Tribunal (CAT), the test had been modified to allow all retailers to make small groceries extensions to stores provided that the store in question has not been extended in the previous five years.'The CC believes that this modification will not significantly reduce the effectiveness of the test but will recognize the fact that such small extensions, if prevented by the test, would be less likely to prompt a rival development,' the Commission said. It added that the analysis it carried out after having its proposals referred back to it by the CAT after Tesco's appeal, 'Concluded that the benefits from the Test would substantially outweigh any costs arising from it'.