Although Table 16-2 shows that the income tax system in the UK is progressive

thus reflects a concern about vertical equity. Table 16-5 Sources of tax revenue in 1983 (percentage of total taxes) A second principle is sometimes applied in discussing the extent to which unequal people should be treated unequally. The benefits principle argues that people who receive more than their share of public spending should pay more than their share of tax revenues. Car users should pay more towards public roads than people without a car should pay. And to some extent they do. Car users pay heavy duties on petrol and must pay licence fees for running a car. However, the benefits principle often conflicts directly with the principle of ability to pay. If people who are most vulnerable to unemployment must pay the highest contributions to the government unemployment insurance scheme, it becomes very difficult to achieve a significant redistribution of income, wealth, or welfare. If the main objective is vertical equity, the ability to pay. principle must usually take precedence. Although Table 16-2 shows that the income tax system in the UK is progressive, it is the entire structure of taxes