22In that Schedule, after paragraph 12A insert—E+W+S+N.I.
“12B(1)In a case involving a relevant situation brought about carelessly by a participator (or a person acting on behalf of a participator), an assessment (or an amendment of an assessment) under this Schedule on the participator may be made at any time not more than 6 years after the end of the relevant chargeable period (subject to sub-paragraph (2)).
(2)In a case involving a relevant situation brought about deliberately by a participator (or a person acting on behalf of a participator), an assessment (or an amendment of an assessment) on the participator may be made at any time not more than 20 years after the end of the relevant chargeable period.
(3)“Relevant situation” means a situation in which—
(a)there is a loss of tax,
(b)the assessable profit charged to tax by or stated in an assessment for a chargeable period ought to be or to have been larger,
(c)the allowable loss stated in an assessment or a determination of loss for a chargeable period ought to be or to have been smaller, or
(d)an assessment to tax should have been made for a chargeable period but was not made.
(4)“Relevant chargeable period” means—
(a)in the case of a further assessment under paragraph 12(2), the chargeable period in which the excessive allowable loss accrued, and
(b)in any other case, the chargeable period to which the assessment relates.
(5)Where the participator carried on a trade or business with one or more other persons at any time in the chargeable period for which the assessment under sub-paragraph (1) or (2) is made, an assessment to tax in respect of the profits of that trade or business may also be made on any of the participator's partners.
(6)In determining the amount of the tax to be charged on a person for a chargeable period in an assessment in a case mentioned in sub-paragraph (1) or (2) (including an assessment under sub-paragraph (5)), effect must be given to any relief or allowance to which that person would have been entitled for that period if a valid claim or application had been made.
(7)Sub-paragraph (6) only applies if the person on whom the assessment is made so requires.
(8)Subsections (5) to (7) of section 118 of the Taxes Management Act 1970 (losses and situations brought about carelessly or deliberately) apply for the purposes of this paragraph as they apply for the purposes of that Act.
(9)In subsection (6)(b) of that section (as it applies for the purposes of this paragraph), the reference to the person who provides the information has effect as if it included any person who becomes the responsible person for the oil field after the information is provided.”