Cotter v Revenue and Customs Commissioners [2013] UKSC 69, [2013] All ER (D) 68 (Nov)
Where a taxpayer had included information in his tax return but had left it to the Revenue to calculate the tax which he was due to pay, the Revenue was entitled to treat as irrelevant to that calculation information and claims which clearly did not, as a matter of law, affect the tax chargeable and payable in the relevant year of assessment. It was clear from ss 8(1) and 8(1AA) of the Taxes Management Act 1970 that the purpose of a tax return was to establish the amounts of income tax and capital gains tax chargeable for a year of assessment and the amount of income tax payable for that year. In the context of ss 8(1), 9, 9A and 42 of the Act, a tax return referred to the information in the tax return form which was submitted for the purpose of establishing the amounts in which a person was chargeable to income tax and capital gains tax for the relevant year of
