Your deadline is 31 January
It is a good tactic to confront anyone who advocates “ability to pay” tax systems to ask them if they have completed their Self-Assessment Return, and how they found HMRC’s rabbit warren of a web site. You have to submit a return even if you own nothing. The forms themselves do not take too much trouble to fill in. Collecting the information they ask for is the trouble. Why do they need to know that I received about a fiver in bank interest? The explanatory forms would need a lawyer to interpret. Honest citizens should not be subjected to this kind of imposition.