If you haven’t filed your tax return yet, you’re too late now. The deadline to file on paper was 30 June. You still have two weeks to file online.
If you do not file your tax return or if you file it late, there are not really any penalties unless you are a repeat offender. And if there is a penalty, it is 10 or 20 % of the tax you still have to pay. And since the tax has been paid during the year, the penalties should not be too high.
However, the taxman has another way to make you pay for it. He can ignore your tax return and deduce your taxable income from estimates and force you to prove what your actual taxable income is - and that is not a nice position to be in. However, for most of us, our income is what it is and there is not much we can do about it.
Anyway, if you are late, there is a backup solution. If you are late, go and see an accountant or a tax adviser; they can file their clients’ tax returns until October 29. Of course, there will be a fee to pay, but they may come up with some tax deductions that you were not aware about.