“198 General Rule (1) The general rule is that the basis period for a tax year is the period of 12 months ending with the accounting date in that tax year.”
“197 Meaning of “accounting date” (1) In this chapter ‘accounting date’, in relation to a tax year, means- (a) the date in the tax year to which accounts are drawn up, or (b) if there are two or more such dates, the latest of them. (2) This is subject to– (a) section 211(2) (middle date treated as accounting date), and (b) section 214(3) (date treated as accounting date if date changed in tax year in which there is no accounting date).”
“214 When a change of accounting date occurs (1) If there is a change from one accounting date (“the old accounting date”) to another accounting date (“the new accounting date”), the change of accounting date occurs— (a) in the first tax year in which accounts are drawn up to the new accounting date, or (b) if earlier, in the first tax year in which accounts are not drawn up to the old accounting date. … 216 Change of accounting date in later tax year (1) This section applies if— (a) a change of accounting date occurs in a tax year in which a person carries on a trade, (b) the tax year is later than the third tax year in which the person carries on the trade, and (c) the person does not permanently cease to carry on the trade in the tax year. (2) If— (a) the conditions in section 217 are met (conditions for basis period to end with new accounting date), and (b) the new accounting date falls less than 12 months after the end of the basis period for the previous tax year, the basis period is that given by the general rule in section 198. (3) If— (a) the conditions in section 217 are met, and (b) the new accounting date falls more than 12 months after the end of the basis period for the previous tax year, the basis period begins immediately after the end of the basis period for the previous tax year and ends with the accounting date. (4) If the conditions in section 217 are not met, the basis period for the tax year is the period of 12 months ending with the old accounting date. 217 Conditions for basis period to end with new accounting date (1) The conditions in this section are met if— (a) the person carrying on the trade gives appropriate notice of the change of accounting date to an officer of Revenue and Customs (see subsection (2)), (b) the 18 month test is met (see subsection (3)), and (c) either condition A or B is met (see subsections (4) to (6)). (2) Appropriate notice of the change of accounting date is given to an officer of Revenue and Customs if (and only if) the notice is given— (a) in a return under the provision of TMA 1970 that applies to the person carrying on a trade (see section 8, 8A or 12AA of that Act), and (b) on or before the day on which the return is required to be made and delivered under that provision. (3) The 18 month test is met if the period of account ending— (a) with the new accounting date in the tax year in which the change of accounting date occurs, or (b) if there is no new accounting date in that tax year, with the new accounting date in the first tax year in which accounts are drawn up to the new accounting date, is not longer than 18 months. (4) Condition A is that, in the 5 tax years immediately before the tax year in which the change of accounting date occurs, there has been no change of accounting date that counts for the purposes of this condition. (5) A change of accounting date counts for the purposes of condition A if it results in the basis period for the tax year in which the change occurs ending with the accounting date in that tax year. (6) Condition B is that— (a) the change of accounting date is made for commercial reasons (see section 218), and (b) the notice under subsection (2) sets out the reasons for the change.”
“989 Definitions The following definitions apply for the purposes of the Income Taxes Acts- … “period of account” -- (a) in relation to a person, means any period for which the person draws up accounts, and (b) in relation to a trade, profession, vocation or other business, means any period for which the accounts of the business are drawn up.”
“In conclusion, I consider that the Long Accounts were the accounts which matter for the purposes of s 217; I consider that they are the only accounts for that period which could be described as Mr Grint’s business accounts; and even if wrong on that, and both could properly be described as business accounts, then the Long Accounts were more important than the Schedule Accounts. This is because the Long Accounts, unlike the Schedule Accounts, were: (a) signed as such by Mr Grint; (b) intended to be and actually were a reasonably accurate record of Mr Grint’s financial performance over the period to which they related; (c) contained a record of the accounting policies used in their preparation; (d) used by his accountants in discussion with Mr Grint to report to him his financial performance over the 20-month period; (e) used as step in process of preparing Mr Grint’s tax return. 183.