UK tax year is the duration within which HMRC calculates the tax on income of persons and business. It begins on 6 April and runs out on 5 April in the succeeding year. By way of example, the tax year 2024 /25 will start on 6 April 2024 and end on 5 April 2025. In the process, individuals and companies have to monitor the income, expenditure and other taxable events. Tax returns and payment of taxes are usually pegged on income during this tax year.

Source: https://accountinglads.com/uk-tax-year/