Anyone who has taxable sources of income besides wages from employment would do well to get on the phone to their accountant as soon as possible.

That is because midnight this Friday is the “first deadline” for tax returns for the financial year 2004-2005.

Of course, this deadline is not a deadline in the full sense of the word: there are no penalties or sanctions for failing to submit anything at this stage of the year.

However, with nine million people having to self-assess themselves for tax each year, it is understandable that the Inland Revenue is keen to encourage early submissions.

As such, anyone who has submitted their returns for 2004-2005 before midnight tonight will have their tax liability calculated for them by the Inland Revenue – while anyone who submits it between Saturday and January 31 next year will have to calculate this for themselves.

“If you have even slightly complex tax affairs, it can be very difficult to work out your own tax bill, so getting the Revenue to do it for you is a good idea”, warned Chas Roy-Chowdury, head of taxation at the Association of Chartered Certified Accountants.

This year, to make things easier, the Inland Revenue has published a short version of the notoriously complex self-assessment form.

But even the full version is reasonably straightforward – if you have all your paperwork on hand, and you have the right forms.

John Whiting, former president of the Chartered Institute of Taxation told the Sunday Herald newspaper: “Everyone gets the basic set of pages, but there are extra sections – such as rental pages, employment pages, capital gains pages – which come with the return. If you don’t have all the pages you need, call the Revenue, or download them from its website.”

Experts recommend that you collect up all documents relating to tax returns as you receive them and put them all in one place.

If you are particularly organised, it may make sense to categorise these from the outset.

Anyone who makes money that has not have PAYE tax deductions made may be required to assess themselves. Everyone knows that this includes self-employed people, but it also includes people who receive capital gains, or rent, who will also be required to present proofs of rental income and expenses.

Higher rate taxpayers are also often required to assess themselves in respect of interest paid on savings. Many banks and building societies only deduct tax at the basic rate of income tax, leaving you to work out what else you owe in addition.

The most simple, but also the most vital advice is to check your return before you send it – many returns are rejected because the personal details or a signature have been left off.

It is also highly recommended to make a copy of your return before filing it.

Finally, never take a letter from the Inland Revenue received in previous tax years saying that you do not need to assess yourself as meaning that you will not have to for this year. If your circumstances have changed, then previous advice may be nullified.

Good luck to all the self-assessors reading!