11(1)A receipt or expense within paragraph 9 or 10 is to be treated as arising over the period of 10 years beginning with 1 January 2013.
(2)The amount of the receipt or expense apportioned to (and treated as arising in) any accounting period falling wholly or partly in that 10-year period is to be determined in proportion to the number of days of the accounting period falling within that 10-year period.
(3)This paragraph does not apply to a receipt which consists of a relevant court-protected item within the meaning of paragraph 12.
(4)This paragraph is subject to paragraphs 13 to 15 (transfers and cessation of business etc).