The allocation of accounting profits to basis periods for tax purposes was repealed from the tax year 2024/25 and replaced by a tax year basis. The rules which apply for the tax year 2024/25 onwards are set out in the Tax year basis from 2024/25 onwards guidance note and the rules for the transitional tax year of 2023/24 including businesses starting in 2023/24 are set out in the Basis period transitional rules 2023/24 guidance note. The details below therefore only apply for tax years up to and including 2022/23.