(1) Where -
(a) an assessment to income tax (in this section referred to as the 'original assessment') has been made for any year of assessment on an individual, or on an individual's trustee, guardian or committee (in this section referred to as the 'representative'), or on an individual's executors or administrators,
(b) the Revenue Commissioners are of the opinion that, if an application for separate assessment under section 1023 had been in force with respect to that year of assessment, an assessment in respect of or of part of the same income would have been made on, or on the representative of, or on the executors or administrators of, an individual who is the spouse of the individual referred to in paragraph (a) or who was the spouse of the individual referred to in paragraph (a) (in this subsection and in subsection (2) referred to as the 'spouse') in that year of assessment, and
(c) the whole or part of the amount payable under the original assessment has remained unpaid at t
…