34(1)
Subject to the following provisions of this Act, and to any other provisions of the Taxes Acts allowing a longer period in any particular class of case, an assessment to income tax or capital gains tax may be made at any time not more than 4 years after the end of the year of assessment to which it relates.
34(1A)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
34(2)
An objection to the making of any assessment on the ground that the time limit for making it has expired shall only be made on an appeal against the assessment.
34(3)
In this section "assessment" does not include a self-assessment.