R. BACON and W. Eltis have argued, in their interesting and provocative book, that the economic diseases Britain has experienced since the 1970s largely stem from the growth of the public sector (or what they call the non-market sector) of the economy.' They support their thesis with empirical evidence and provide underlying economic theory. An investigation of the economic consequences of the growth of the public sector is crucially important, especially as it is a matter of deep concern to most of the developed countries today, which still have large public sectors in spite of their recent policies to halt such growth.2 Although there has been some argument on the Bacon and Eltis thesis since publication of their book,3 the underlying theory has not as yet been closely examined within the framework of a coherent economic model. Accordingly, this paper investigates the effects of non-market sector growth in a simple but consistent model, constructed, we might add, in the spirit of the Bacon and Eltis approach. Our model enables us to analyze the problem more comprehensively and precisely than theirs. We will examine how the economic effects of the growth of the non-market sector will differ depending on: (i) whether we consider the short-run or the long-run; (ii) whether we consider the case of under-employment or the case of fullemployment; (iii) whether we assume the budget to be balanced or not; and finally, (iv) whether the increase in government expenditure is directed toward marketed output or concentrated in payment to persons in the public service. After examining these cases closely, we will point out that although there can surely arise Bacon and Eltis case wherein an increase in the relative size of the non-market sector induces high rate of inflation, high rate of unemployment and low rate of investment, the increase in the relative size of the non-market sector itself may rather be the result than the cause of the low propensity of entrepreneurs to undertake investment.