Q. The Taxman has written to me saying I missed a small pension worth about £800 a year from my last tax return. He hasn't noticed that I also missed it off the last four tax returns. What should I do?

A. Best advice is to come clean immediately and tell the Taxman about all the missing amounts of pension income for all tax years. There may not be more tax to pay if the pension provider has already deducted tax at your marginal tax rate. However, if there is higher rate tax to pay there will also be interest due at 3% and possibly a penalty. By confessing all without delay you can qualify for a reduced penalty, down to say 15% of the tax due. We can help you with those penalty negotiations and may be able to get it suspended for up to two years.

All my income is taxed under PAYE, so surely I don't need to complete a tax form, do I?

Q. I've received a £100 fine for not submitting my tax return, but I don't remember receiving a form to complete. All my income is taxed under PAYE, so surely I don't need to complete a tax form, do I?

A. You should first ring the Self Assessment helpline on 0845 900 0444. Have to hand your NI number and your unique taxpayer reference number (UTR), if you know it. The Tax Officer will confirm whether you need to complete a tax return for the year to 5 April 2011 or not. If you do need to complete a tax return for that year you should do that online, if you submit a paper form now you will receive an even higher penalty. We can help you submit your return online, if one is due.

I received my self-assessment statement and payslip on 17 August 2011, which shows tax due to be paid by 31 July 2011

Q. I received my self-assessment statement and payslip on 17 August 2011, which shows tax due to be paid by 31 July 2011. I paid the tax due as soon as I could, but I am now worried that I will get charged interest and a penalty for late payment.

A. The late issuing of these statements was due to a lack of paper at HMRC's printers! As the delay was essentially their fault HMRC has decided to waive the interest due, as long as the tax payment is received by 27 September 2011. However, this interest free period only applies to the second payment on account of income tax for 2010/11, due by 31 July 2011. Any other late tax payments, such as tax due by 31 January 2011 will accrue interest as normal.

Help! I've received two tax calculations from the Taxman that say I owe £4,500 for 2007/08 and £7,200 for 2008/09. What should I do?

Q. Help! I've received two tax calculations from the Taxman that say I owe £4,500 for 2007/08 and £7,200 for 2008/09. I didn't complete tax returns for those years as I was employed in several short-term contracts. What should I do?

A. First check the tax computations. The calculation for 2008/09 probably includes the tax due brought forward from 2007/08, so you may only owe £7,200 not £11,700 (£7,200 + £4,500). Next try to find your P60 and P45 forms, and any payslips for those tax years, and check the figures on those forms against the tax calculations. We can help you with this. Don't worry if you haven't retained those papers as the law only requires you to keep then until 31 January 2010, or 31 January 2011 for the later year.

If you had good reason to believe that your tax affairs were in order for 2007/08 you may be able to ask HMRC to write-off the tax underpaid from that year under Extra Statutory Concession A19. You can also ask for the tax for 2008/09 to be collected over 36 months, if it is actually due.