The Principal Act is amended -

(a) in section 1017 by inserting the following after subsection (2):

"(3) Subject to subsection (4), for a year of assessment prior to the current year of assessment in which this section applies as a consequence of -

(a) an election made (including an election deemed to have been duly made) under section 1018,

(b) an election made under section 1019(2)(a)(ii), or

(c) section 1019(4)(a),

a husband or a wife who is not assessed under this section may elect to be so assessed and such election shall apply in place of any earlier election or deemed election for that year of assessment.

(4) Subsection (3) shall not apply where the husband or the wife is a chargeable person (within the meaning of section 959A).",

and

(b) in section 1031C by inserting the following after subsection (2):