95(1)The writing-down period for an item of qualifying expenditure—
(a)begins at the beginning of the chargeable period in respect of which the expenditure is incurred, and
(b)is of a length determined in accordance with the Table, which shows the basic rule, and the rules which apply instead of the basic rule in the cases described in items 2 and 3.
Length of writing-down periods for qualifying expenditure
| Rule | Length of writing-down period |
|---|---|
| 1. Basic rule. | 17 years. |
| 2. Patent rights are purchased for a specified period. | Whichever is shorter— (a) 17 years; (b) the number of years comprised within the specified period. |
| 3. Patent rights begin one complete year or more after the commencement of the patent, and item 2 does not apply. | 17 years, less the number of complete years which, when the rights began, have elapsed since the commencement of the patent; orif 17 complete years have so elapsed, one year. |
(2)For the purpose of determining the writing-down period, expenditure incurred for the purposes of a trade by a person about to carry on the trade is treated as if incurred on the first day on which that person carries on that trade, unless that person has by then sold all the rights on which the expenditure was incurred.
(3)“The commencement of the patent”, means, in relation to a patent, the date as from which the patent rights become effective.