Sch 15 para 44
The total activated TTH amount for a loss period is to be allocated, for the purposes of the application of paragraph 25 in relation to that loss period, to pre-acquisition accounting periods of the purchaser as follows— Step 1 Take the most recent pre-acquisition accounting period for which there is an unused transferred profits amount which is greater than nil. Step 2 Allocate to that pre-acquisition accounting period an amount equal to the lower of— the unused transferred profits amount, and the total activated TTH amount held by the purchaser for the loss period. Step 3 Allocate to the next most recent pre-acquisition accounting period an amount equal to the lower of— the transferred profits amount for that period, and the available activated TTH amount for the loss period. Step 4 Repeat Step 3 (taking later pre-acquisition accounting periods before earlier ones) until the amount given by paragraph (a) or (b) is nil.