"We thought HMRC meant we didn't have to pay tax" said a Amazon/Starbucks/and a few others' spokesman "Because our accountants said the purpose of tax is to tax people, so when HMRC said that tax didn't have to be taxing we thought they meant we didn't really have to pay it. So we didn't."
HMRC are currently focus-grouping the new slogan "Tax should be fucking-well Taxing, you bastards" to see if that works.