Oil Taxation Act 1975

12(1)Where it appears to the Board—U.K.

(a)that the assessable profit charged to tax by or stated in an assessment ought to be or to have been larger or smaller; or

(b)that the allowable loss stated in an assessment or a determination of loss ought to be or to have been larger or smaller; or

(c)that, where they made a determination that neither an assessable profit nor an allowable loss accrued in a chargeable period, they ought to have made an assessment to tax or a determination of loss for that period, [F1or]

[F2(d)that for any chargeable period they ought to have made an assessment to tax instead of a determination of loss or a determination of loss instead of an assessment to tax];

the Board may make such assessments or determinations or such amendments of assessments or determinations as may be necessary; and where the Board exercise any of their powers under this paragraph in relation to a chargeable period, they may make such [F3assessments or determinations or amendments of assessments or determinations] for other chargeable periods as may be necessary in consequence of the exercise of those powers[F4and “taxable field” and “non-taxable field” have the same meaning as in Part III of the Finance Act 1993].

[F5(1A)An assessment (or an amendment of an assessment) under sub-paragraph (1) may be made at any time not more than 4 years after the end of the chargeable period to which the assessment relates (subject to sub-paragraph (1B) and paragraphs 12A and 12B).

(1B)The time limits in sub-paragraph (1A) and paragraphs 12A and 12B do not apply to an amendment of an assessment where the amendment is made in consequence (directly or indirectly) of—

(a)the granting of relief under section 7(2) or (3) to any participator for allowable losses accruing in any chargeable period, F6...

[F7(aa)a claim under paragraph 13A (see paragraph 13E), or]

(b)a notice of variation served under paragraph 9 of Schedule 5 on any responsible person in respect of a claim for any claim period.]

(2)Where under sub-paragraph (1) above it appears to the Board that the assessable profit for a chargeable period ought to have been larger and that the deficiency resulted from an excessive allowable loss accruing in a subsequent period having been set against the profit for that period, the Board may F8... make a further assessment by virtue of sub-paragraph (1) above at any time not later than [F94 years] after the end of the chargeable period in which the allowable loss accrued [F10(subject to paragraphs 12A and 12B)] .

[F11(3)Where under this paragraph the Board make an assessment or determination or amend an assessment or determination they shall give notice thereof to the participator concerned; and sub-paragraphs (4), (5) and (6) of paragraph 10 above shall apply in relation to any such assessment, determination or amendment as they apply in relation to an assessment or determination under that paragraph.]