Taxman and elephantDavid Cheskin/PA Archive/Press Association Images

Tax experts have revealed a major new series of mistakes from the taxman. HMRC is apparently making serious errors when estimating whether you have paid the right amount of tax.

So could you be a victim?

Tax miscalculations

Accountancy firm Kingston Smith is warning taxpayers that the taxman may well be making serious mistakes on their P800 tax calculations. These forms are sent to taxpayers when HMRC thinks that they have paid too much or too little tax.

The problem is that the income figures on the form are just estimates (something which isn't entirely clear from the form itself). They are based on the previous year's known sources of income, which could vary significantly from the actual figures. The firm says there have been a spate of incidents where taxpayers were given inaccurate figures.


Accountant Andrew Shaw, explains: "When taxpayers receive a letter on official HMRC paper detailing their tax liability, many naturally assume that the numbers are correct. Our experience shows that this is not always the case, often because some of the figures used represent last year's known income."

He continues: "Whilst the earnings taxed under PAYE are usually correct, the figures indicating other sources of income are sometimes simply wrong. This can occur for any number of reasons – for example, if the taxpayer's dividends or bank interest have changed since the previous year, which is more likely than not.

Shaw urges: "Taxpayers who receive a P800 Tax Calculation should always check the numbers against their own records and notify HMRC immediately of any discrepancies; unfortunately, once again HMRC cannot be trusted to get it right."

Self-assessment headaches

The accountants also reveal a host of problems related to those completing self-assessment tax returns for the January 31 deadline. HMRC has apparently issued a host of unnecessary tax return reminders about the online filing deadline to Self Assessment taxpayers who have already filed, and in some cases paid the tax due on, their tax returns.

A number of the letters – some of which were dated as early as 5 December, but were not received by taxpayers until over a month later – have been wasted on taxpayers who had already met the online Self Assessment deadline for online filing last year.

If you receive a reminder, it is always best to double-check your online account to see if there is anything left outstanding. It will be clear from your login whether the form has been submitted or not and whether they is any money outstanding. This is a more up-to-date record than the letters ever can be.

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