From the start of April, a new system comes into force to determine the size of the penalty payable if you make an inaccurate tax return and pay too little tax.
Up until now, this has been a bit of a grey area. Carelessness would generally attract no penalty at all. Obviously, you'd have to pay the tax that was due - these penalties are *in addition* to the tax payable - and interest as the tax had been paid late, but nothing else. On the other hand, systematic dishonesty could attract a penalty of up to 100% of the tax due - and criminal prosecution in some cases, of course. But all this was at the discretion of the Revenue and varied from tax officer to tax officer and from tax office to tax office.
Now, the penalties are being set down in law, and carelessness may be more costly. If you fail to take, in the words of the new rules, "reasonable care" and consequently make a mistake on your tax return, the basic penalty will be 30%. However, this will be reduced if you notify the Revenue of the underpayment. If you do this "out of blue" because you've noticed the error, the penalty can be waived entirely. If you do it because the Revenue has noticed that something's wrong - although they're not sure exactly what - then it can be reduced to 15%.
At the top end, for dishonesty, 100% remains the "baseline" penalty, though it can be reduced if the taxpayer either confesses, or is helpful once he has been found out.
The good news is that, if you use an accountant, and they make a mistake, you should be OK - as long as a) you've appointed an adviser who you could reasonably expect to be competent and b) you gave them all the information they needed to get the return right. If that's the case, the carelessness will be accepted as theirs, not yours, and should not result in a tax penalty.
There's lots of coverage of this change within the profession at the moment. It's also being suggested that accountants should make their clients aware of the change, to deter them from either dishonesty or carelessness in future. Personally, I would hope that accountants already make it clear to their clients that making dishonest tax returns is not a great idea! But I will make sure our clients know that carelessness or incomplete disclosure of information may result in harsher penalties in future.