- If you miss the self assessment deadline, a late tax return penalty of £100 will be issued by an automated process at HMRC.
- If you still have not filed three months after the deadline, you will also start clocking up automatic £10 per day penalties – up to a maximum of £900.
- If you still have not filed six months after the deadline, in addition to the penalties above, you will have to pay a further penalty of £300 or 5% of the tax liability, whichever is higher.
- If you still have not filed a year after the deadline, in addition to the penalties above, you will have to pay a further £300 or up to 100% of the tax due as a penalty.
The penalty for the late payment of the tax is different and will apply from 28 February. The penalty is 5% of the tax unpaid.
There will be another 5% penalty for the outstanding tax six months after the filing deadline. This will be followed by another 5% penalty for payments that are 12 months late.
As with the tax return these amounts mount up and each penalty is subject to interest.