(1) Section 239 of the Principal Act is amended -
(a) in subsection (4) by inserting ", but in any event not later than day 21 of the month in which that period of 9 months ends" after "the end of that period", and
(b) in subsection (5) by substituting "corporation tax" for "preliminary tax" and by inserting "in accordance with section 958 and" after "payable by the company".
(2) This section has effect for accounting periods commencing on or after 14 October 2008.