Unless a tax underpayment arises under PAYE, HMRC will issue a Self-Assessment Tax Calculation showing their calculation of the amount of tax due. This form SA302 creates a legally enforceable debt. HMRC may also issue a “Statement of Account”, or an “Annual Tax Summary” but these are not formal demands for tax.
The Self-Assessment calculation should always be checked carefully to ensure that it is correct and based on full information.
The form SA302 will show the income tax due for the tax year and the date on which this amount is due. The due date for payment of these amounts may already have passed if the tax return was filed close to the deadline date of January 31st and interest on late payment of tax will be charged.
If the tax due for the year is over £1,000 the calculation will also show the amounts and dates of payments on account for the next tax year. The first of these payments is due on January 31, so interest may be charged on this amount as well.
You can request a reduction in the payments on account, if you anticipate that taxable income for the next tax year will be lower, so that the final amount of tax due will be less. This can be done online or by post using form SA303. As interest is due on a late payment of payment on account, you should therefore only request a reduction in a payment on account if your income is reduced, not because of a difficulty in payment.
