A comprehensive guide to Corporation Tax in the UK, detailing its application to company profits, including trading income, investments, and capital gains. It explains the current progressive tax structure introduced post-April 2023, which includes a Small Profit Rate (19%), a Main Rate (25%), and a Marginal Relief mechanism to smooth the transition between the two rates. The text outlines the three-step process for calculating tax liability: determining Total Profits (Trading Profits plus Capital Gains), applying available Reliefs such as Rollover Relief, and calculating the final tax due. Furthermore, the source addresses the tax treatment of Capital Gains and highlights that, unlike income tax, companies receive No "Personal Allowance" before concluding with information on Payment Deadlines and the taxation of Distributions to shareholders, such as dividends and deemed distributions.