The tax return guidance and other forms we send you give plenty of warning about deadline dates. It is your own responsibility to make sure you meet the deadlines. Surcharges are charged for certain late payments. Penalties are charged for late tax returns. This booklet tells you about surcharges.
Interest is charged on any amount paid late.
If your tax return is late you are liable to penalties. In addition, if we think you have not paid enough tax on time we may issue you with a 'determination of tax due'. This tells you our estimate of your tax bill for the year. You cannot appeal against this estimate. The only way to change the amount you have to pay is by sending in your completed tax return.