General rules
26.—(1) Where a fixed asset investment of a description falling to be included under Assets items 7 (Participating interests) or 8 (Shares in group undertakings) in the balance sheet format, or any other holding of securities held as a financial fixed asset, has diminished in value, provisions for diminution in value may be made in respect of it and the amount to be included in respect of it may be reduced accordingly; and any such provisions which are not shown in the profit and loss account shall be disclosed (either separately or in aggregate) in a note to the accounts.
(2) Provisions for diminution in value shall be made in respect of any fixed asset which has diminished in value if the reduction in its value is expected to be permanent (whether its useful economic life is limited or not), and the amount to be included in respect of it shall be reduced accordingly; and any such provisions which are not shown in the profit and loss account shall be disclosed (either separately or in aggregate) in a note to the accounts.
(3) Where the reasons for which any provision was made in accordance with sub-paragraph (1) or (2) have ceased to apply to any extent, that provision shall be written back to the extent that it is no longer necessary; and any amounts written back in accordance with this sub-paragraph which are not shown in the profit and loss account shall be disclosed (either separately or in aggregate) in a note to the accounts.