22Assessments
(1)The profits or gains arising to a person for any chargeable period which are assessable to tax under Schedule A may, if they arise from more than one source, be assessed in one or more assessments, and in the latter case, each assessment may relate to profits or gains from one or more sources.
(2)Subject to subsection (3) below, where an assessment to income tax under Schedule A for any year of assessment is made in that year—
(a)it shall be made on the basis that all sources of income and all amounts relevant in computing profits or gains are the same as for the last preceding year of assessment, and
(b)tax shall be leviable accordingly, but any necessary adjustments shall be made after the end of the year, whether by way of assessment, repayment of tax or otherwise, to secure that tax is charged by reference to the rents or receipts to which the person assessed becomes entitled in the year of assessment.
(3)If before the 1st January in any year a person delivers a statement in writing to the inspector—
(a)showing that since the beginning of the last preceding year of assessment he has ceased to possess one or more sources of income chargeable under Schedule A, and
(b)giving the aggregate of the rents and receipts relevant for the purposes of Schedule A to which he has become or is likely to become entitled in the current year (“the current aggregate”), and
(c)showing that the current aggregate is less than the aggregate of such rents and receipts to which he became entitled in the last preceding year (“the previous aggregate”), and that it would not have been less if he had not ceased to possess the said source or sources,
then, if the inspector is satisfied as to the correctness of the statement, an assessment made on that person in the current year shall be made on an amount which bears to the amount arrived at under subsection (2)(a) above the same proportion as the current aggregate bears to the previous aggregate, and subsection (2)(b) above shall apply accordingly.