The Income Tax (Indexation) Order 1990
Sections 1(6) and 257C(3) of the Income and Corporation Taxes Act 1988 (“the Act”) provide that the Treasury shall by order made by statutory instrument before 6th April 1990 specify the amounts which by virtue of those sections shall, unless Parliament otherwise determines, be treated as specified for the year 1990—91. These are the basic rate limit (section 1 of the Act) and the personal and married couple’s allowances (sections 257 and 257A of the Act) respectively.