DIRT is a tax on the wealthy, those people who have excess capital which they keep in the form of cash. More particularly it is a tax on the old as they are the ones who have the excess capital, mainly acquired through the capital inflation of their pensions and homes rather than through earned income.DIRT is a tax on middle people, the poorest save nothing and aim to draw the maximum from the state, the wealthy have complex investment provisions. Bu even if relatively poor people save something, there is no allowance or threshold for DIRT.