Greg Wood: "The Tax Office are being very firm about the cut-off date"

Not all is lost. You have until Sunday, 31 January, to save your bacon and quite a bit of money.

And if you have completely lost your tax form, you may be able to download it from the Inland Revenue's web site.

One weekend should be enough time to carry out your self-assessment, tick all the boxes, gather old receipts and fill in the right numbers.

There is just one problem: You will have to do all calculations yourself. Had you returned the form by 30 September last year, the taxman would have helped you.

Tax offices are staying open to take those last minute forms

But the Inland Revenue is still happy to give you advice if you are lost in the self-assessment jungle.

All tax offices will be open this weekend to provide counselling for stressed tax payers and accept tax returns and the money that goes with them.

Most revenue offices will be open between 1000 and 1500 on Saturday and Sunday. Check your local newspaper for the opening times in your area. The Inland Revenue has taken out advertisements to bring dawdling tax payers up-to-date.

Help will also be given on a special self-assessment helpline. Call 0645 000 444 and tax experts will answer your questions.

The Internet is another mine of information. Visit the Inland Revenue web site on www.inlandrevenue.gov.uk/sa/ where you will find detailed information on what you have to do.

Meet the taxman

Once you have filled in the tax return, you have to rush to the nearest tax office and submit it. It is now too late to rely on the post.

Your tax return must be with the Inland Revenue on Sunday.

Well, you actually have a short period of grace until early Monday morning. Any tax return pushed through the letter box of any tax office before it opens on 1 February will be accepted as having been delivered on time.

There is only one consolation: You will not have to take your return to the office that holds your file. Any UK tax office will do.

Paying up

Remember: Submitting the paperwork is not enough. You have to pay up as well. The Inland Revenue expects you to pay your tax in full by 31 January.

Hector will be unforgiving after 31 January

Tax offices will accept cash, although they prefer a cheque.

The cheque should be made out to the Inland Revenue, not Gordon Brown or your local MP.

Interesting payments

Once you have submitted your tax return, it will be checked. Because you left it so late, it is up to you to get it right.

If you underpay, the tax office will soon ask for the rest and demand interest payments for any outstanding money - at a healthy rate of 8.5%.

Too late

But what if you miss the deadline?

You will still have to pay and it could cost you dear.

Missing the self-assessment deadline carries an automatic fine of £100. If you dawdle another six months this will rise to £200.

Your outstanding tax will accrue interest payments, as you effectively have taken out a loan with the taxman. At 8.5% this may be cheaper than the debt payments on your credit card, but not everybody will be happy about it.

Sometime in February, you will receive a new tax statement, detailing your fine, how much money you owe and how much interest you have to pay. The longer you wait, the more expensive it gets.