The crisis which brought Greece to the brink of bankruptcy in 2009 and onwards was in part due to the inability of successive governments to take in enough tax to cover their costs. More recently, at the end of 2023, the population’s total outstanding debt to the public purse was estimated to be €80 billion, or 20 per cent of the national debt (the latter, at around €400 billion or 162% of GDP for the same year, being the 4th highest in the world in percentage terms). But this was only the figure for established debts, many of which will have been for unpaid income tax. Equally, if not more important, is the potential tax due on undeclared incomes.