How to deal with a letter from the taxman

tax error

HM revenue & customs have just begun the first wave of a three month process informing six million taxpayers that they have paid the wrong tax. 

The first batch of 45,000 letters hitting the doormat this week will go to some of the 4.3 million individuals who are lucky enough to be due a rebate averaging £420 each, while others will be received by some of the 1.8 million taxpayers who have underpaid, on average by £1,400. 

Why the letters?

The tax payment problem arose a while ago when HMRC merged 20 computer systems into one. This resulted in some old data being read as current information. Subsequently, people’s tax codes were incorrect and this affected the amount of tax they paid each month - too much or not enough.

The computer system now shows that HMRC is owed £2 billion through underpaid tax over the past two tax years, but it also revealed that it was overpaid by 1.8bn. 

Some have argued there should be no action on either front, while others question why people should overpay their tax at the expense of those who have underpaid. So the HMRC see that a letter to all those involved is the only way of resolving the issue.

For those with a small underpayment - under £300 - the HMRC will not try to recover the sum.

Is the letter a tax demand?

No, it's a tax calculation, the HMRC’s estimate of the taxpayer’s tax position. The letter is purely information from HMRC of what they think your correct tax code is and whether they owe you, or you owe them, money. Don't panic and confuse this with a tax demand. 

What do I do if I receive a letter saying I owe them money?

Make sure the information in the letter is correct and read the P800 form and guidance notes. For example, it might state that you have more than one job when you don’t, or that you have a company car when you don’t. The form may also not detail any tax relief you are entitled to, so look out for mistakes straightaway.  

Another area to look at is your employer as they may be to blame for not using your personal tax code correctly and deducting the wrong amount of tax from your pay. If so take the issue up with them.   

Can I ask for the debt to be written off?

It is possible under certain circumstances. You will need to see if the letter is out of date and if the revenue has delayed more than a year in informing you about any tax shortfall then you can ask to have the debt written off. 

This will only apply if, when you open the letter, you find that the underpaid tax relates to the 2008-2009 tax year, (more than 12 months old) and importantly that you are satisfied that you provided the tax office with all the information they needed at the time. If so and they failed to act upon it then you can request an 'Extra-Statutory Concession A19' that the debt be written off.

How do I check my tax code?

You can check your tax code at 

You can also use an on-line calculator at to ensure your net pay is right for your circumstances.

My tax code is wrong, what is the best way to contact HMRC?

You can contact HMRC on 0845 3000 627 but be aware they are likely to be extremely busy as a result of this current issue. More contact details will be on your letter and P800 form.

It may be best to write, clearly stating your reasons for your grievance and the tax year concerned, 2008-2009 or 2009 -2010. Make sure you send the letter and any supporting documentation recorded delivery to prove postage and keep a copy of everything. See a template letter here.

What if I genuinely cannot afford to repay the debt?

There is the possibility that HMRC will put pressure on you to pay back all the tax immediately. If this happens you should put in counter-proposals, for example, refusing the new tax code and making alternative arrangements to pay by cash instalments over a period that you can manage. Always remember that any underpayment is not your fault, it was caused by HMRC. 

Can I appeal against my calculation?

If you submit an A19 concession and it is rejected then you can go to a free appeal service run by the Adjudicator’s Office which is seen as a fair and unbiased complaints intermediary for HMRC grievances.

What happens if I am due a rebate or accept I owe money?

Anyone due a rebate will receive a cheque within seven to ten days of receiving the first letter; this will include 0.5% interest! 

If you are one of the unlucky ones that owes money, then provided this is below £2,000 you will receive a new tax code early next year. This new code will come into force in April to enable the collection of any monies owed to be collected throughout that year.

If the amount you owe is above £2,000 then HMRC will write to you and ask for direct payment. If you cannot afford to repay this then you need to contact them to arrange a repayment strategy.

Those in receipt of benefits

This is another issue that has not been resolved as those on very low incomes may have been entitled to higher benefits, denied them through inaccurate tax coding. There is no right to claim backdated benefits.

Scam emails 

All your communication from HMRC will be by letter, they will not send you an email. If you receive an email promising a refund and requiring your bank details, don't open it! It will be a scam and the same applies to any telephone calls from HMRC requesting bank details. 

Most importantly, if you receive a letter regarding overpayment, don’t ignore it, do something about it as the HMRC do not go away.


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