(1) Where for one or more continuous periods of at least 12 months part of an asset has been used wholly and exclusively for the purposes of the tonnage tax activities of a tonnage tax company and part has not, this section shall apply as if the part so used were a separate asset.
(2) Where subsection (1) applies, any necessary apportionment of the gain or loss on the disposal of the whole asset shall be made on a just and reasonable basis.
(a) When an asset is disposed of that is or has been a tonnage tax asset -
(i) any gain or loss on the disposal, which but for this paragraph would have been the amount of the chargeable gain or the allowable loss, shall be a chargeable gain or allowable loss only to the extent (if any) to which it is referable to periods during which the asset was not a tonnage tax asset, and
(ii) any such chargeable gain or allowable loss on a disposal by a tonnage tax company shall be treated as arising otherwise than in the course of the company's tonnage ta
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