2024 Tax Extension Deadline Date Uk. You have until 11.59pm on wednesday 31 january 2024 to send hmrc an online tax return for the 2022/2023 tax year, which ended on 5 april 2023. The deadline for filing your tax return is one year after the end of your company’s last accounting period.
Calendar of tax deadlines and new tax measures. The corporation tax return deadline for most uk businesses is 12 months after the end of the accounting period it covers.