'PLEASE check that information in this notice is correct. If the details are wrong, phone the Helpline because the amount of your award may be too low or too high."

If only it were that easy.

The Inland Revenue only exists as a giant wheeze to ensure that, in this e-age, the Royal Mail still has letters to deliver.

There is a Temporary Tax Code Unit hidden away in a garret churning out letters, each new temporary tax code superseding last week's temporary tax code which replaces the temporary tax code issued the week before. Each new temporary tax code keeps the postman in motion: within four weeks he delivered six new temporary tax codes to a colleague's house in Hetton earlier this year, which is a successful job creation scheme by anyone's standards.

But then came Gordon Brown's child tax credit which was part of his sensible ambition to simplify the tax system. Soon postmen up and down the country were trundling up and down nearly six million garden paths delivering large questionnaires.

Who were they delivering them to? People the taxman already knew were eligible because you had to be eligible to receive a form which, if you filled it in, would decide if you were eligible.

But it was not that simple. Once the taxman had received the form from the eligible people, he decided to invent some questions that he already knew the answer to so that the postman was still in employment.

The question I was sent was: what is your tax reference code? The letter included a helpful little drawing showing where I could find my tax reference code - on top of a letter sent out by the taxman telling me my last temporary tax code.

And who created that tax reference code? Yes, the taxman, who was now asking me what the code was that he had created.

With a long sigh, I sent it back.

Earlier this week, the postman dumped through the letterbox the taxman's final calculation.

We'll overlook the fact that this final calculation is flawed before it was even begun: he is using information from 2001-02 to calculate our tax credit for 2003-04, and in the period 2002-03 the number of children in our household has increased by 100 per cent while our income has plummeted by 50 per cent. We'll overlook this because the Temporary Tax Code Unit will keep countless postmen in work sorting it out.

Anyway, the final calculation has worked out that in 2001-02 I earned £40,000 more than I did - even though the taxman knows precisely what I earned because he taxed me on it.

"This is based on the facts shown below, so please check that they are correct. If they are wrong please phone the Helpline," exhorts the taxman's final calculation. But the Helpline is so engaged that on at least 50 occasions this week I've heard a BT message telling me: "The telephone network is busy. Please try again later."

Once, early yesterday morning, I made it through to the taxman's pre-recorded message. He made me choose from a whole series of options - none of which were applicable - before concluding: "We are currently experiencing high call volumes and cannot process your call. Please call again later." Then he rang off.

I did get through to the Northern Ireland Helpline for people with hearing or speech difficulties. It was unable to help, so it wasn't really a Helpline.

I'll have to write. The postman will be happy.