“Subject to sub-paragraphs (3) to (7) below, a person who makes taxable supplies but is not registered under this Act becomes liable to be registered under this Schedule— (a) at the end of any month, if the person is UK-established and the value of his taxable supplies in the period of one year then ending has exceeded£79,000 ;”
"81. When considering a "reasonable excuse" defence, therefore, in our view the FTT can usefully approach matters in the following way: (1) First, establish what facts the taxpayer asserts give rise to a reasonable excuse (this may include the belief, acts or omissions of the taxpayer or any other person, the taxpayer's own experience or relevant attributes, the situation of the taxpayer at any relevant time and any other relevant external facts). (2) Second, decide which of those facts are proven. (3) Third, decide whether, viewed objectively, those proven facts do indeed amount to an objectively reasonable excuse for the default and the time when that objectively reasonable excuse ceased. In doing so, it should take into account the experience and other relevant attributes of the taxpayer and the situation in which the taxpayer found himself at the relevant time or times. It might assist the FTT, in this context, to ask itself the question "was what the taxpayer did (or omitted to do or believed) objectively reasonable for this taxpayer in those circumstances?" (4) Fourth, having decided when any reasonable excuse ceased, decide whether the taxpayer remedied the failure without unreasonable delay after that time (unless, exceptionally, the failure was remedied before the reasonable excuse ceased). In doing so, the FTT should again decide the matter objectively, but taking into account the experience and other relevant attributes of the taxpayer and the situation in which the taxpayer found himself at the relevant time or times."
"82. One situation that can sometimes cause difficulties is when the taxpayer's asserted reasonable excuse is purely that he/she did not know of the particular requirement that has been shown to have been breached. It is a much-cited aphorism that " ignorance of the law is no excuse", and on occasion this has been given as a reason why the defence of reasonable excuse cannot be available in such circumstances. We see no basis for this argument. Some requirements of the law are well-known, simple and straightforward but others are much less so. It will be a matter of judgment for the FTT in each case whether it was objectively reasonable for the particular taxpayer, in the circumstances of the case, to have been ignorant of the requirement in question, and for how long. The Clean Car Co itself provides an example of such a situation."