421(1) This section determines the amount of the income under section 417 when a qualifying change in the interest of the partner company in a business of leasing plant or machinery occurs on any day (“the relevant day”).
421(2) The amount of the income is found by–
(a)applying the formula in subsection (3) to give the basic amount, and
(b)making such adjustment to the basic amount as is required in accordance with section 422 or 423.
421(3) The formula is–
PM − TWDV
421(4) In this section “PM” has the meaning given by section 400, but–