18The interest of the group in subsidiary undertakings excluded from consolidation under section 229(4) (undertakings with activities different from those of undertakings included in the consolidation), and the amount of profit or loss attributable to such an interest, shall be shown in the consolidated balance sheet or, as the case may be, in the consolidated profit and loss account by the equity method of accounting (including dealing with any goodwill arising in accordance with paragraphs 17 to 19 and 21 of Schedule 4).