(1)Where the Board have determined under Schedule 2 to this Act that an allowable loss has accrued to a participator in a chargeable period from an oil field, then, subject to the following provisions of this section, the assessable profit accruing to him from the field in any succeeding chargeable period shall be treated as reduced by the amount of that allowable loss, or by so much of that amount as cannot, under this subsection or on a claim (if made) under subsection (2) below, be relieved against the assessable profit accruing to him from the field in any earlier chargeable period.
(2)Where the Board have determined under Schedule 2 to this Act that an allowable loss has accrued to a participator in a chargeable period from an oil field, the participator may make a claim requiring that the loss be in the first instance set against any assessable profit which accrued to him from the field in any preceding chargeable period; and the assessable profit which so accrued to him in any such period shall then be treated as reduced by the amount of the loss, or by so much of that amount as cannot be relieved under this subsection against any assessable profit accruing to him from the field in a later chargeable period.
(3)Where—
(a)the Board have determined under Schedule 2 to this Act that an allowable loss has accrued to a participator in a chargeable period from an oil field ; and
(b)the winning of oil from that field has permanently ceased,
then so much of that allowable loss as cannot under subsection (1) or (2) above be relieved against assessable profits accruing to the participator from the field shall be relieved under this subsection by treating the assessable profit accruing to him from the field in any chargeable period as reduced by the amount of the loss, or by so much of that amount as cannot be relieved under this section against the assessable profit so accruing to him in a later chargeable period.