The fines for not submitting a tax return are unfortunately quite severe now… and also apply even if you don’t owe any tax or are in fact due a refund:
• After 31st January – £100 late return penalty
• After 3 months late – £10 per day for up to 90 days, then
• After 6 months late – the greater of £300 or 5% of the tax due
• After 12 months late – the greater of £300 or 5% of the tax due
So failing to submit a return for a year, even if there is no tax due, could cost up to £1600 in fines.
In addition there are also possible tax penalties on top of up to 100% for incorrect declarations or failing to notify HMRC.