(1) Section 81 of the Principal Act is amended -

(a) in subsection (2) -

(i) in paragraph (o), by substituting "relief;" for "relief.", and

(ii) by inserting the following paragraph after paragraph (o):

"(p) any taxes on income.",

and

(b) by inserting the following subsection after subsection (3):

"(4) In this section, 'doubtful debts to the extent that they are respectively estimated to be bad' means, in respect of a company, impairment losses as calculated in accordance with generally accepted accounting practice.".

(2) Subsection (1)(b) shall be deemed to have applied as respects accounting periods beginning on or after 1 January 2018.