Oil Taxation Act 1975

11 (1) Where a participator has under paragraph 2 above delivered to the Board a return for a chargeable period and the Board are satisfied that the information given in the return is correct in so far as it is material for the purpose of computing his assessable profit or allowable loss (if any) for that period, the Board shall (in so far as the computation falls to be made by reference to the matters dealt with in the return) make the assessment or determination under paragraph 10 above in accordance with the return.

(2) Where the Board are not so satisfied in relation to a participator's return or a participator fails to deliver to the Board a return for a chargeable period as required by paragraph 2 above, the Board shall, in so far as the computation of his assessable profit or allowable loss (if any) for that period falls to be made by reference to the matters which were dealt with in the return or, as the case may be, ought to have been dealt with in a return, make the assessment or determination under paragraph 10 above to the best of their judgment.

(3) Nothing in sub-paragraph (2) above or in paragraph 5 above shall be taken, in a case where the participator has delivered a return as to which the Board are not satisfied as mentioned in sub-paragraph (1) above, to prevent the Board from basing their assessment or determination on the participator's having had an interest in oil won and saved from the field different from that on which he based his return.