A tax return is a document that must be sent to HMRC to declare a tax liability. Companies must declare a number of tax liabilities on separate tax returns, such as Corporation Tax and VAT. Individuals who are PAYE workers, who have their tax taken from their wages from their employer and returned to HMRC on their behalf, do not have an obligation to file an income tax return unless they have additional income, for example from savings or investments. The tax year runs every year from 6th April to 5th April, and a tax must be filed within 9 months of the end of the tax year, ie. before 31st January the following year.