Liability on amalgamation: intercompany supplies before the order date remain taxable and registrations persist until that date. Where a merger or amalgamation order operates from a date earlier than the order date, supplies or receipts between constituent companies from that operative date until the order date must be included in each company's turnover and taxed; notwithstanding the retrospective effect, the companies are treated as distinct companies for the interim period and their registrations are cancelled with effect from the order date.